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A274306
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a(n) = Product_{k=1..n} (4*k^4+1).
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2
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1, 5, 325, 105625, 108265625, 270772328125, 1403954521328125, 13484983177356640625, 220951449360988556640625, 5798870788479144669033203125, 231960630409954265905997158203125, 13584774319958971582784723570166015625
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n) ~ (1 + cosh(Pi)) * 2^(2*n + 2) * n^(4*n + 2) / exp(4*n). - Vaclav Kotesovec, Oct 10 2016
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MATHEMATICA
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Table[Product[4*k^4+1, {k, 1, n}], {n, 0, 15}] (* Vaclav Kotesovec, Oct 10 2016 *)
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PROG
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(PARI) a(n) = prod(k=1, n, 4*k^4+1); \\ Michel Marcus, Oct 10 2016
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CROSSREFS
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For squares in this sequence see A274307.
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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