A308463 a(n) = Sum_{k=1..n, gcd(n,k) = 1} Stirling2(n,k).

1, 1, 4, 7, 51, 16, 876, 2045, 15475, 15256, 678569, 2006863, 27644436, 46065293, 669225640, 5235101739, 82864869803, 234937438645, 5832742205056, 25117329128165, 235703526149476, 1886712616836675, 44152005855084345, 102153081219673712, 3428690854204959151

Offset

1,3

Links

Table of n, a(n) for n=1..25.

Mathematica

a[n_] := Sum[If[GCD[n, k] == 1, StirlingS2[n, k] , 0], {k, 1, n}]; Table[a[n], {n, 1, 25}]

Prog

(PARI) a(n) = sum(k=1, n, if (gcd(n, k)==1, stirling(n, k, 2))); \\ Michel Marcus, May 28 2019

Crossrefs

Cf. A000110, A008277, A056188, A096314, A308037.

Sequence in context: A094609 A249936 A049191 * A261672 A013467 A330450

Adjacent sequences: A308460 A308461 A308462 * A308464 A308465 A308466

Keyword

nonn

Author

Ilya Gutkovskiy, May 28 2019

Status

approved