emmevi Cushion Cover Sofa 42 x 42 cm Solid Color Zippered Cushion Cover

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This sum of three cubes puzzle, first set in 1954 at the University of Cambridge and known as the Diophantine Equation x 3+y 3+z 3=k, challenged mathematicians to find solutions for numbers 1-100. With smaller numbers, this type of equation is easier to solve: for example, 29 could be written as 3 3 + 1 3 + 1 3, while 32 is unsolvable. All were eventually solved, or proved unsolvable, using various techniques and supercomputers, except for two numbers: 33 and 42.

The problem is stated as follows: What integers n can be written as the sum of three whole-number cubes ( n = a 3 + b 3 + c 3)? And for such integers, how do you find a, b and c ? As a practical matter, the difficulty in making this calculation is that for a given n, the space of the triplets to be considered involves negative integers. This triplet space is therefore infinite, unlike the computation for the sum of squares. For that particular problem, any solution has an absolute value lower than the square root of a given n. Moreover for the sum of squares, we know perfectly well what is possible and impossible. Apart from allusions to 42 deliberately introduced by computer scientists for fun and the inevitable encounters with it that crop up when you poke around a bit in history or the world, you might still wonder whether there is anything special about the number from a strictly mathematical point of view. Mathematically Unique? In 2009, employing a method proposed by Noam Elkies of Harvard University in 2000, German mathematicians Andreas-Stephan Elsenhans and Jörg Jahnel explored all the triplets a, b, c of integers with an absolute value less than 10 14 to find solutions for n between 1 and 1,000. The paper reporting their findings concluded that the question of the existence of a solution for numbers below 1,000 remained open only for 33, 42, 74, 114, 165, 390, 579, 627, 633, 732, 795, 906, 921 and 975. For integers less than 100, just three enigmas remained: 33, 42 and 74. Ancient Tibet had 42 rulers. Nyatri Tsenpo, who reigned around 127 B.C., was the first. And Langdarma, who ruled from 836 to 842 A.D. (i.e., the 42nd year of the ninth century), was the last.Forty-two is a Catalan number. These numbers are extremely rare, much more so than prime numbers: only 14 of the former are lower than one billion. Catalan numbers were first mentioned, under another name, by Swiss mathematician Leonhard Euler, who wanted to know how many different ways an n-sided convex polygon could be cut into triangles by connecting vertices with line segments. The beginning of the sequence ( A000108 in OEIS) is 1, 1, 2, 5, 14, 42, 132.... The nth element of the sequence is given by the formula c( n) = (2 n)! / ( n!( n + 1)!). And like the two preceding sequences, the density of numbers is null at infinity. To illustrate how difficult it is to find solutions to the equation n = a 3 + b 3 + c 3, let’s see what happens for n = 1 and n = 2. A question that naturally follows is: Is there at least one solution for every nonprohibited value? Computers at Work An infinite set of solutions is also known for n = 2. It was discovered in 1908 by mathematician A. S. Werebrusov. For any integer p: The centimeter (symbol: cm) is a unit of length in the metric system. It is also the base unit in the centimeter-gram-second system of units. The centimeter practical unit of length for many everyday measurements. A centimeter is equal to 0.01 (or 1E-2) meter. Centimeters to inches formula and conversion factor

But both are more interested in a simpler but computationally more challenging puzzle: whether there are more answers for the sum of three cubes for 3. For practical purposes we can round our final result to an approximate numerical value. We can say that forty-two centimeters is approximately sixteen point five three five inches: The number 42 is the sum of the first two nonzero integer powers of six—that is, 6 1 + 6 2 = 42. The sequence b( n), which is the sum of the powers of six, corresponds to entry A105281 in OEIS. It is defined by the formulas b(0) = 0, b( n) = 6 b( n– 1) + 6. The density of these numbers also tends toward zero at infinity. The difficulty appears so daunting that the question “Is n a sum of three cubes?” may be undecidable. In other words, no algorithm, however clever, may be able to process all possible cases. In 1936, for example, Alan Turing showed that no algorithm can solve the halting problem for every possible computer program. But here we are in a readily describable, purely mathematical domain. If we could prove such undecidability, that would be a novelty.The marathon distance of 42.195 kilometers corresponds to the legend of how far the ancient Greek messenger Pheidippides traveled between Marathon and Athens to announce victory over the Persians in 490 B.C. (The fact that the kilometer had not yet been defined at that time only makes the connection all the more astonishing.) An inch (symbol: in) is a unit of length. It is defined as 1⁄12 of a foot, also is 1⁄36 of a yard. Though traditional standards for the exact length of an inch have varied, it is equal to exactly 25.4 mm. The inch is a popularly used customary unit of length in the United States, Canada, and the United Kingdom. Definition of centimeter

When I heard the news, it was definitely a fist-pump moment,” says Sutherland. “With these large-scale computations you pour a lot of time and energy into optimizing the implementation, tweaking the parameters, and then testing and retesting the code over weeks and months, never really knowing if all the effort is going to pay off, so it is extremely satisfying when it does.”

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mod 9); 1 3 = 1 (mod 9); 2 3 = 8 = –1 (mod 9); 3 3 = 27 = 0 (mod 9); 4 3 = 64 = 1 (mod 9); 5 3 = (–4) 3 = –64 = –1 (mod 9); 6 3 = (–3) 3 = 0 (mod 9); 7 3 = (–2) 3 = 1 (mod 9); 8 3 = (–1) 3 = –1 (mod 9) Booker and Sutherland discussed the algorithmic strategy to be used in the search for a solution to 42. As Booker found with his solution to 33, they knew they didn’t have to resort to trying all of the possibilities for x, y, and z.