A320963 a(n) = Sum_{j=0..n} Sum_{k=0..j} abs( Stirling1(j - k, k) ).

1, 1, 2, 3, 6, 15, 51, 227, 1257, 8296, 63394, 549740, 5330185, 57117590, 670163058, 8543228103, 117564576721, 1736762231296, 27411856376831, 460320540171210, 8194312180092795, 154127845115561811, 3054239953905841713, 63597989583700047353, 1388275729125313815336

Offset: 0

Author

Peter Luschny, Nov 06 2018

Keywords

• nonn

Links

• Andrew Howroyd, Table of n, a(n) for n = 0..200

Crossrefs

The Stirling_2 counterpart: A320964.

Programs

Maple

a := n -> add(add(abs(Stirling1(j - k, k)), k=0..j), j=0..n):
seq(a(n), n=0..29);

Mathematica

a[n_] := Sum[Sum[Abs[StirlingS1[j - k, k]], {k, 0, j}], {j, 0, n}];
Array[a, 25, 0] (* Amiram Eldar, Nov 06 2018 *)

PARI

a(n)={sum(j=0, n, sum(k=0, j, abs(stirling(j-k, k, 1))))} \\ Andrew Howroyd, Nov 06 2018