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

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.

Sequence in context: A326196 A222084 A327394 * A085082 A335516 A335549

Adjacent sequences: A088870 A088871 A088872 * A088874 A088875 A088876

Keyword

easy,nonn

Author

Naohiro Nomoto, Nov 30 2003

Status

approved