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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
OFFSET
1,2
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
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Nov 02 2021
STATUS
approved