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A047799
a(n) = Sum_{k=0..n} C(n,k)*Stirling1(n,k)^2.
2
1, 1, 3, 40, 1015, 40631, 2334766, 180836664, 18067408311, 2254675244287, 342877692847261, 62311687363814736, 13318714515734069806, 3304254169559017642774, 940912768920331123369272, 304601441677789509306775856
OFFSET
0,3
LINKS
MAPLE
seq(add(binomial(n, k)*stirling1(n, k)^2, k = 0..n), n = 0..20); # G. C. Greubel, Aug 07 2019
MATHEMATICA
Table[Sum[Binomial[n, k]*StirlingS1[n, k]^2, {k, 0, n}], {n, 0, 20}] (* G. C. Greubel, Aug 07 2019 *)
PROG
(PARI) {a(n) = sum(k=0, n, binomial(n, k)*stirling(n, k, 1)^2)};
vector(20, n, n--; a(n)) \\ G. C. Greubel, Aug 07 2019
(Magma) [(&+[Binomial(n, k)*StirlingFirst(n, k)^2: k in [0..n]]): n in [0..20]]; // G. C. Greubel, Aug 07 2019
(Sage) [sum(binomial(n, k)*stirling_number1(n, k)^2 for k in (0..n)) for n in (0..20)] # G. C. Greubel, Aug 07 2019
(GAP) List([0..20], n-> Sum([0..n], k-> Binomial(n, k)*Stirling1(n, k)^2 )) # G. C. Greubel, Aug 07 2019
CROSSREFS
KEYWORD
nonn
STATUS
approved