A348856 a(n) = Sum_{d|n} (Stirling2(n,d) mod 2).

1, 2, 2, 3, 2, 3, 2, 4, 3, 4, 2, 4, 2, 3, 3, 5, 2, 5, 2, 5, 3, 3, 2, 5, 3, 3, 4, 4, 2, 5, 2, 6, 3, 4, 3, 7, 2, 3, 3, 6, 2, 5, 2, 4, 4, 3, 2, 6, 2, 5, 4, 4, 2, 5, 2, 5, 4, 3, 2, 6, 2, 3, 4, 7, 3, 5, 2, 6, 3, 5, 2, 8, 2, 4, 4, 4, 3, 5, 2, 7, 4, 4, 2, 6, 4, 3, 3, 5, 2, 7, 3, 4, 3, 3, 2, 7, 2, 3, 6, 6

Offset

1,2

Links

Table of n, a(n) for n=1..100.

Mathematica

Table[DivisorSum[n, Mod[StirlingS2[n, #], 2] &], {n, 1, 100}]

Prog

(PARI) a(n) = sumdiv(n, d, stirling(n, d, 2) % 2); \\ Michel Marcus, Nov 02 2021

Crossrefs

Cf. A007306, A008277, A246600, A308037.

Sequence in context: A067554 A135981 A135615 * A166469 A080226 A060741

Adjacent sequences: A348853 A348854 A348855 * A348857 A348858 A348859

Keyword

nonn

Author

Ilya Gutkovskiy, Nov 02 2021

Status

approved