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A242280
a(n) = Sum_{k=0..n} (k!*StirlingS2(n,k))^3.
4
1, 1, 9, 433, 63225, 18954001, 10159366329, 8924902306993, 11969476975085625, 23232038620328946001, 62655369716047066046649, 227268291642918880258797553, 1079475019974966974009683584825, 6565863403062578428919598754170001
OFFSET
0,3
COMMENTS
Generally, for p>=1 is Sum_{k=0..n} (k!*StirlingS2(n,k))^p asymptotic to n^(p*n+1/2) * sqrt(Pi/(2*p*(1-log(2))^(p-1))) / (exp(p*n) * log(2)^(p*n+1)).
LINKS
FORMULA
a(n) ~ sqrt(Pi/6) * n^(3*n+1/2) / ((1-log(2)) * exp(3*n) * (log(2))^(3*n+1)).
MATHEMATICA
Table[Sum[(k!)^3 * StirlingS2[n, k]^3, {k, 0, n}], {n, 0, 20}]
CROSSREFS
Sequence in context: A271652 A156092 A092813 * A266294 A273889 A167720
KEYWORD
nonn,easy
AUTHOR
Vaclav Kotesovec, May 10 2014
STATUS
approved