This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS 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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 8 09:32 EST 2019. Contains 329862 sequences. (Running on oeis4.)