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A373519
Expansion of e.g.f. exp(x/(1 - x^4)^(1/4)).
4
1, 1, 1, 1, 1, 31, 181, 631, 1681, 60481, 687961, 4379761, 19982161, 802740511, 13848694861, 131732390791, 873339798241, 38385869907841, 894783905472241, 11506538747852641, 101612306808695521, 4824806928717603871, 142148609212891008421
OFFSET
0,6
FORMULA
a(n) = n! * Sum_{k=0..floor(n/4)} binomial(n/4-1,k)/(n-4*k)!.
a(n) == 1 mod 30.
PROG
(PARI) a(n) = n!*sum(k=0, n\4, binomial(n/4-1, k)/(n-4*k)!);
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jun 08 2024
STATUS
approved