A348856 - OEIS

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A348856

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

0

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

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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