A373524 Expansion of e.g.f. exp(x * (1 + x^4)^(1/4)).
1, 1, 1, 1, 1, 31, 181, 631, 1681, -30239, -219239, -609839, 23761, 348686911, 2769787021, 8683865191, 519049441, -13487418759359, -125598814684559, -446790263130719, 15237796321, 1447967425273506271, 15403882866996490021, 61625443167286653271, 1295472977069041
Offset: 0
Keywords
Programs
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PARI
a(n) = n!*sum(k=0, n\4, binomial(n/4-k, k)/(n-4*k)!);
Formula
a(n) = n! * Sum_{k=0..floor(n/4)} binomial(n/4-k,k)/(n-4*k)!.
a(n) == 1 mod 30.