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A368771
a(n) = (n!)^3 * Sum_{k=0..n} k^2/(k!)^3.
4
0, 1, 12, 333, 21328, 2666025, 575861436, 197520472597, 101130481969728, 73724121355931793, 73724121355931793100, 98126805524745216616221, 169563119946759734312830032, 372530174523031136285287580473, 1022222798891197437966829120818108
OFFSET
0,3
FORMULA
a(0) = 0; a(n) = n^3 * a(n-1) + n^2.
a(n) = n^2 * A368775(n-1) for n > 0.
PROG
(PARI) a(n) = n!^3*sum(k=0, n, k^2/k!^3);
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jan 05 2024
STATUS
approved