A373525 Expansion of e.g.f. exp(x * (1 + x^4)^(1/2)).

1, 1, 1, 1, 1, 61, 361, 1261, 3361, -37799, 15121, 2522521, 20005921, 486563221, 363363001, -12486293819, 3113772481, -12960051533519, 8909829442081, 528011239172401, 241435513794241, 1381310884267333741, 3097715443570441, -49080307628073705059

Offset

0,6

Links

Table of n, a(n) for n=0..23.

Formula

a(n) = n! * Sum_{k=0..floor(n/4)} binomial(n/2-2*k,k)/(n-4*k)!.

a(n) == 1 mod 60.

Prog

(PARI) a(n) = n!*sum(k=0, n\4, binomial(n/2-2*k, k)/(n-4*k)!);

Crossrefs

Cf. A190877, A373524, A373526.

Cf. A373520.

Sequence in context: A245763 A130117 A361673 * A357965 A353225 A373520

Adjacent sequences: A373522 A373523 A373524 * A373526 A373527 A373528

Keyword

sign

Author

Seiichi Manyama, Jun 08 2024

Status

approved