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Joseph Madachy
Joseph Steven Madachy (March 16, 1927 – March 27, 2014) was a research chemist, technical editor and recreational mathematician. He was the lead editor of '' Journal of Recreational Mathematics'' for nearly 30 years and then served as editor emeritus. He was owner, publisher and editor of its predecessor, ''Recreational Mathematics Magazine,'' which appeared from 1961–1964. Early life and education Madachy was born in Star Junction, Pennsylvania, to Steven and Anne Madachy. He was raised in Cleveland, Ohio. He became interested in recreational mathematics after reading Eugene Northrop's 1944 book, ''Riddles in Mathematics''. After service in World War II, he attended Western Reserve University on the G.I. Bill and earned a bachelor's and a master's in Chemistry. Career Madachy moved to Dayton, Ohio, and worked for Mound Laboratories. He made original contributions to the field of recreational mathematics. In 1960 he wrote to recreational mathematician Martin Gardner, aski ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Recreational Mathematics
Recreational mathematics is mathematics carried out for recreation (entertainment) rather than as a strictly research and application-based professional activity or as a part of a student's formal education. Although it is not necessarily limited to being an endeavor for amateurs, many topics in this field require no knowledge of advanced mathematics. Recreational mathematics involves mathematical puzzles and games, often appealing to children and untrained adults, inspiring their further study of the subject. The Mathematical Association of America (MAA) includes recreational mathematics as one of its seventeen Special Interest Groups, commenting: Mathematical competitions (such as those sponsored by mathematical associations) are also categorized under recreational mathematics. Topics Some of the more well-known topics in recreational mathematics are Rubik's Cubes, magic squares, fractals, logic puzzles and mathematical chess problems, but this area of mathematics incl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyomino
A polyomino is a plane geometric figure formed by joining one or more equal squares edge to edge. It is a polyform whose cells are squares. It may be regarded as a finite subset of the regular square tiling. Polyominoes have been used in popular puzzles since at least 1907, and the enumeration of pentominoes is dated to antiquity. Many results with the pieces of 1 to 6 squares were first published in ''Fairy Chess Review'' between the years 1937 to 1957, under the name of "dissection problems." The name ''polyomino'' was invented by Solomon W. Golomb in 1953, and it was popularized by Martin Gardner in a November 1960 "Mathematical Games" column in ''Scientific American''. Related to polyominoes are polyiamonds, formed from equilateral triangles; polyhexes, formed from regular hexagons; and other plane polyforms. Polyominoes have been generalized to higher dimensions by joining cubes to form polycubes, or hypercubes to form polyhypercubes. In statistical physics, the study ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1927 Births
Nineteen or 19 may refer to: * 19 (number), the natural number following 18 and preceding 20 * one of the years 19 BC, AD 19, 1919, 2019 Films * ''19'' (film), a 2001 Japanese film * ''Nineteen'' (film), a 1987 science fiction film Music * 19 (band), a Japanese pop music duo Albums * ''19'' (Adele album), 2008 * ''19'', a 2003 album by Alsou * ''19'', a 2006 album by Evan Yo * ''19'', a 2018 album by MHD * ''19'', one half of the double album ''63/19'' by Kool A.D. * ''Number Nineteen'', a 1971 album by American jazz pianist Mal Waldron * ''XIX'' (EP), a 2019 EP by 1the9 Songs * "19" (song), a 1985 song by British musician Paul Hardcastle. * "Nineteen", a song by Bad4Good from the 1992 album '' Refugee'' * "Nineteen", a song by Karma to Burn from the 2001 album ''Almost Heathen''. * "Nineteen" (song), a 2007 song by American singer Billy Ray Cyrus. * "Nineteen", a song by Tegan and Sara from the 2007 album '' The Con''. * "XIX" (song), a 2014 song by Slipk ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perfect Digit-to-digit Invariant
In number theory, a perfect digit-to-digit invariant (PDDI; also known as a Munchausen number) is a natural number in a given number base b that is equal to the sum of its digits each raised to the power of itself. An example in base 10 is 3435, because 3435 = 3^3 + 4^4 + 3^3 + 5^5. The term "Munchausen number" was coined by Dutch mathematician and software engineer Daan van Berkel in 2009, as this evokes the story of Baron Munchausen raising himself up by his own ponytail because each digit is raised to the power of itself.Daan van Berkel,''On a curious property of 3435.''/ref> Definition Let n be a natural number which can be written in base b as the k-digit number d_d_...d_d_ where each digit d_i is between 0 and b-1 inclusive, and n = \sum_^ d_b^. We define the function F_b : \mathbb \rightarrow \mathbb as F_b(n) = \sum_^ ^. (As 00 is usually undefined, there are typically two conventions used, one where it is taken to be equal to one, and another where it is taken to be equal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Never Go Back (Lee Child Novel)
''Never Go Back'' is the eighteenth book in the Jack Reacher series written by Lee Child.Never Go Back LeeChild.com – Never Go Back It was published on 3 September 2013 in the United States.Amazon.com – Never Go Back /ref> The book continues the storyline covered in the novels '' 61 Hours'', '' Worth Dying For'' and ''''. The novel, like ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jack Reacher
Jack Reacher is the protagonist of a series of crime thriller novels by British author Lee Child. In the stories, Jack Reacher was a major in the US Army's military police. Having left the Army at age 36, Reacher roams the United States, taking odd jobs and investigating suspicious and frequently dangerous situations. , 27 novels plus some short stories have been published. The most recent novel is ''No Plan B''. Three novels have been adapted for the screen. Two of the adaptations are films, starring Tom Cruise as Reacher: ''Jack Reacher'' (2012) from the ninth novel, '' One Shot'', and '' Jack Reacher: Never Go Back'' (2016) from the eighteenth novel, '' Never Go Back''. The third adaption is a television series on Amazon Prime Video, starring Alan Ritchson: '' Reacher'' (2022). This was adapted from the first novel, '' Killing Floor''. Development and author's commentary Development At the time Lee Child sat down to write his first novel '' Killing Floor'', he was une ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentomino Puzzle Solutions
Derived from the Greek word for ' 5', and " domino", a pentomino (or 5-omino) is a polyomino of order 5, that is, a polygon in the plane made of 5 equal-sized squares connected edge-to-edge. When rotations and reflections are not considered to be distinct shapes, there are 12 different ''free'' pentominoes. When reflections are considered distinct, there are 18 '' one-sided'' pentominoes. When rotations are also considered distinct, there are 63 ''fixed'' pentominoes. Pentomino tiling puzzles and games are popular in recreational mathematics. Usually, video games such as '' Tetris'' imitations and ''Rampart'' consider mirror reflections to be distinct, and thus use the full set of 18 one-sided pentominoes. Each of the twelve pentominoes satisfies the Conway criterion; hence every pentomino is capable of tiling the plane. Each chiral pentomino can tile the plane without being reflected. History The earliest puzzle containing a complete set of pentominoes appeared in Henr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calculator Art
An electronic calculator is typically a portable Electronics, electronic device used to perform calculations, ranging from basic arithmetic to complex mathematics. The first Solid-state electronics, solid-state electronic calculator was created in the early 1960s. Pocket-sized devices became available in the 1970s, especially after the Intel 4004, the first microprocessor, was developed by Intel for the Japanese calculator company Busicom. Modern electronic calculators vary from cheap, give-away, ISO/IEC 7810, credit-card-sized models to sturdy desktop models with built-in printers. They became popular in the mid-1970s as the incorporation of integrated circuits reduced their size and cost. By the end of that decade, prices had dropped to the point where a basic calculator was affordable to most and they became common in schools. Computer operating systems as far back as Ancient UNIX, early Unix have included interactive calculator Computer program, programs such as dc (comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magic Square
In recreational mathematics, a square array of numbers, usually positive integers, is called a magic square if the sums of the numbers in each row, each column, and both main diagonals are the same. The 'order' of the magic square is the number of integers along one side (''n''), and the constant sum is called the ' magic constant'. If the array includes just the positive integers 1,2,...,n^2, the magic square is said to be 'normal'. Some authors take magic square to mean normal magic square. Magic squares that include repeated entries do not fall under this definition and are referred to as 'trivial'. Some well-known examples, including the Sagrada Família magic square and the Parker square are trivial in this sense. When all the rows and columns but not both diagonals sum to the magic constant this gives a ''semimagic square (sometimes called orthomagic square). The mathematical study of magic squares typically deals with their construction, classification, and enumeration. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fibonacci Number
In mathematics, the Fibonacci numbers, commonly denoted , form a sequence, the Fibonacci sequence, in which each number is the sum of the two preceding ones. The sequence commonly starts from 0 and 1, although some authors start the sequence from 1 and 1 or sometimes (as did Fibonacci) from 1 and 2. Starting from 0 and 1, the first few values in the sequence are: :0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. The Fibonacci numbers were first described in Indian mathematics, as early as 200 BC in work by Pingala on enumerating possible patterns of Sanskrit poetry formed from syllables of two lengths. They are named after the Italian mathematician Leonardo of Pisa, later known as Fibonacci, who introduced the sequence to Western European mathematics in his 1202 book ''Liber Abaci''. Fibonacci numbers appear unexpectedly often in mathematics, so much so that there is an entire journal dedicated to their study, the ''Fibonacci Quarterly''. Applications of Fibonacci numbers include co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Narcissistic Number
In number theory, a narcissistic number 1 F_ : \mathbb \rightarrow \mathbb to be the following: : F_(n) = \sum_^ d_i^k. where k = \lfloor \log_ \rfloor + 1 is the number of digits in the number in base b, and : d_i = \frac is the value of each digit of the number. A natural number n is a narcissistic number if it is a fixed point for F_, which occurs if F_(n) = n. The natural numbers 0 \leq n 0: digit_count = digit_count + 1 y = y // b total = 0 while x > 0: total = total + pow(x % b, digit_count) x = x // b return total def ppdif_cycle(x, b): seen = [] while x not in seen: seen.append(x) x = ppdif(x, b) cycle = [] while x not in cycle: cycle.append(x) x = ppdif(x, b) return cycle The following Python program determines whether the integer entered is a Narcissistic / Armstrong number or not. def no_of_digits(num): i = 0 while num > 0: num //= 10 i+=1 retu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
