The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A350495 a(n) is the constant term in expansion of Product_{k=1..n} (x^(k^2) + 1/x^(k^2))^2. 2
 1, 2, 4, 8, 16, 40, 88, 222, 570, 1564, 4516, 13874, 41866, 137432, 442964, 1492610, 4998674, 17204844, 59175316, 207299554, 727137516, 2582078416, 9179001124, 32943918428, 118453240846, 428937325964, 1556421977612, 5676923326262, 20754245720206 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Vaclav Kotesovec, Table of n, a(n) for n = 0..200 FORMULA Conjecture: a(n) ~ sqrt(5) * 4^n / (sqrt(Pi) * n^(5/2)). - Vaclav Kotesovec, Feb 05 2022 MAPLE b:= proc(n) option remember; `if`(n=0, 1, expand((x^(n^2)+1/x^(n^2))^2*b(n-1))) end: a:= n-> coeff(b(n), x, 0): seq(a(n), n=0..28); # Alois P. Heinz, Jan 28 2022 MATHEMATICA Table[Coefficient[Product[(x^(k^2) + 1/x^(k^2))^2, {k, 1, n}], x, 0], {n, 0, 30}] (* Vaclav Kotesovec, Feb 05 2022 *) CROSSREFS Cf. A000980, A047653, A158092, A350249, A350881. Sequence in context: A344491 A028497 A197244 * A337581 A259377 A275071 Adjacent sequences: A350492 A350493 A350494 * A350496 A350497 A350498 KEYWORD nonn AUTHOR Ilya Gutkovskiy, Jan 28 2022 STATUS approved

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

Last modified September 24 00:14 EDT 2023. Contains 365554 sequences. (Running on oeis4.)