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Search: id:A092959
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| A092959 |
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Least square of the form 'product of n successive terms of an arithmetic progression + 1', or 0 if no such square exists. |
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+0
2
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| 4, 4, 16, 25, 121, 5041, 5041, 0, 2504902401, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Conjecture: No term is zero.
All terms in the progression are required to be positive. Zero values are highly probable but unproved. I have checked for each a(n) up to 10^(3*n+8). - David Wasserman (dwasserm(AT)earthlink.net), Aug 11 2006
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EXAMPLE
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a(3) = 16 = 1*3*5 + 1, a(4) = 25 = 1*2*3*4 + 1.
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PROGRAM
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(PARI) f(n, x, y) = prod(i = 0, n - 1, x + i*y) + 1; for (n = 8, 24, LIMIT = 10^(3*n + 8); x = 1; y = 1; num = f(n, 1, 1); while (num < LIMIT, while (num < LIMIT, if (issquare(num), print([n, num])); y++; num = f(n, x, y)); x++; y = 1; num = f(n, x, y))); - David Wasserman (dwasserm(AT)earthlink.net), Aug 11 2006
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CROSSREFS
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Sequence in context: A156232 A053441 A065732 this_sequence A158101 A038234 A099462
Adjacent sequences: A092956 A092957 A092958 this_sequence A092960 A092961 A092962
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KEYWORD
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less,nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Mar 25 2004
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EXTENSIONS
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More terms from David Wasserman (dwasserm(AT)earthlink.net), Aug 11 2006
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