A373526 Expansion of e.g.f. exp(x * (1 + x^4)^(3/4)).
1, 1, 1, 1, 1, 91, 541, 1891, 5041, -22679, 703081, 9397081, 59946481, 510926131, -1770628859, 28435376971, 879567081121, 1118967005521, 133425791669521, -153681150137039, 1206979480409761, 974131304609110411, -2730300052811686739, 68047061689139820211
Offset: 0
Keywords
Programs
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PARI
a(n) = n!*sum(k=0, n\4, binomial(3*n/4-3*k, k)/(n-4*k)!);
Formula
a(n) = n! * Sum_{k=0..floor(n/4)} binomial(3*n/4-3*k,k)/(n-4*k)!.
a(n) == 1 mod 90.