OFFSET
0,3
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..50
FORMULA
a(n)^2 = A127605(n)/(2^n * (2*n+1)).
a(n) ~ sqrt(Gamma(1/4)) * exp(G*(2*n+1)^2/(2*Pi)) / (2^(n/2 + 5/4) * Pi^(3/8) * n^(3/4)), where G is Catalan's constant A006752. - Vaclav Kotesovec, Dec 30 2020
MATHEMATICA
Table[2^(n*(n-1)) * Product[Product[Sin[i*Pi/(2*n + 1)]^2 + Sin[j*Pi/(2*n + 1)]^2, {i, 1, j-1}], {j, 2, n}], {n, 0, 15}] // Round (* Vaclav Kotesovec, Dec 30 2020 *)
PROG
(PARI) default(realprecision, 120);
{a(n) = round(prod(j=2, n, prod(i=1, j-1, 4*sin(i*Pi/(2*n+1))^2+4*sin(j*Pi/(2*n+1))^2)))}
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Dec 29 2020
STATUS
approved