

A277352


a(n) = Product_{k=1..n} (2*k^2+1).


2



1, 3, 27, 513, 16929, 863379, 63026667, 6239640033, 804913564257, 131200910973891, 26371383105752091, 6408246094697758113, 1851983121367652094657, 627822278143634060088723, 246734155310448185614868139, 111277104045012131712305530689
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OFFSET

0,2


LINKS

Table of n, a(n) for n=0..15.


FORMULA

a(n) ~ 2^(n+3/2) * n^(2*n+1) * sinh(Pi/sqrt(2)) / exp(2*n).


MATHEMATICA

Table[Product[2*k^2+1, {k, 1, n}], {n, 0, 15}]


CROSSREFS

Cf. A101686, A277347, A277353, A277354.
Sequence in context: A286306 A285239 A111844 * A118714 A089506 A062496
Adjacent sequences: A277349 A277350 A277351 * A277353 A277354 A277355


KEYWORD

nonn


AUTHOR

Vaclav Kotesovec, Oct 10 2016


STATUS

approved



