A088873 - OEIS

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A088873

Number of different values of A000005(d) where d is a divisor of n.

1, 2, 2, 3, 2, 3, 2, 4, 3, 3, 2, 5, 2, 3, 3, 5, 2, 5, 2, 5, 3, 3, 2, 6, 3, 3, 4, 5, 2, 4, 2, 6, 3, 3, 3, 6, 2, 3, 3, 6, 2, 4, 2, 5, 5, 3, 2, 8, 3, 5, 3, 5, 2, 6, 3, 6, 3, 3, 2, 7, 2, 3, 5, 7, 3, 4, 2, 5, 3, 4, 2, 8, 2, 3, 5, 5, 3, 4, 2, 8, 5, 3, 2, 7, 3, 3, 3, 6, 2, 7, 3, 5, 3, 3, 3, 9, 2, 5, 5, 6, 2, 4, 2, 6

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OFFSET

1,2

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..10000

MATHEMATICA

a[n_] := Length@ DeleteDuplicates[DivisorSigma[0, Divisors[n]]]; Array[a, 100] (* Amiram Eldar, Mar 27 2024 *)

PROG

(PARI) a(n) = {vals = Set(); fordiv(n, d, vals = Set(concat(vals, numdiv(d)))); return (length(vals)); } \\ Michel Marcus, Jul 14 2013

CROSSREFS

Cf. A000005.

Differs from A085082 and A181796 for the first time at n=24, where a(24) = 6, while A085082(24) = A181796(24) = 7.