A136176 - OEIS

A136176

Number of exponents in the prime factorization of n which divide n.

0, 1, 1, 1, 1, 2, 1, 0, 0, 2, 1, 2, 1, 2, 2, 1, 1, 2, 1, 2, 2, 2, 1, 2, 0, 2, 1, 2, 1, 3, 1, 0, 2, 2, 2, 2, 1, 2, 2, 1, 1, 3, 1, 2, 1, 2, 1, 2, 0, 2, 2, 2, 1, 2, 2, 1, 2, 2, 1, 3, 1, 2, 1, 0, 2, 3, 1, 2, 2, 3, 1, 2, 1, 2, 1, 2, 2, 3, 1, 2, 0, 2, 1, 3, 2, 2, 2, 1, 1, 3, 2, 2, 2, 2, 2, 1, 1, 2, 1, 2, 1, 3, 1, 1, 3

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OFFSET

1,6

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..65537

EXAMPLE

128000 = 2^10 * 5^3. 10 divides 128000, but 3 does not. So a(128000) = 1.

MATHEMATICA

Table[Length[Select[Table[FactorInteger[n][[i, 2]], {i, 1, Length[FactorInteger[n]]}], Mod[n, # ] == 0 &]], {n, 1, 90}] (* Stefan Steinerberger, Dec 21 2007 *)

PROG

(PARI) A136176(n)=sum(j=1, #t=factor(n)[, 2]~, !(n%t[j])) \\ M. F. Hasler, Dec 21 2007

CROSSREFS

Cf. A136177.

Sequence in context: A323090 A355935 A180026 * A291914 A303708 A319138

Adjacent sequences: A136173 A136174 A136175 * A136177 A136178 A136179

KEYWORD

nonn,easy

AUTHOR

Leroy Quet, Dec 19 2007

EXTENSIONS

More terms from M. F. Hasler and Stefan Steinerberger, Dec 21 2007

STATUS

approved