

A100587


Number of nonempty subsets of divisors of n.


17



1, 3, 3, 7, 3, 15, 3, 15, 7, 15, 3, 63, 3, 15, 15, 31, 3, 63, 3, 63, 15, 15, 3, 255, 7, 15, 15, 63, 3, 255, 3, 63, 15, 15, 15, 511, 3, 15, 15, 255, 3, 255, 3, 63, 63, 15, 3, 1023, 7, 63, 15, 63, 3, 255, 15, 255, 15, 15, 3, 4095, 3, 15, 63, 127, 15, 255, 3, 63, 15, 255, 3, 4095, 3
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OFFSET

1,2


COMMENTS



LINKS



FORMULA

a(n) = 1 + 2^tau(n), where tau(n) = DivisorSigma(0, n) = A000005(n).


EXAMPLE

For all prime numbers p, a(p)=3, since those subsets are {{1,p},{1},{p}}.


MAPLE



MATHEMATICA



PROG

(Haskell)
a100587 = (subtract 1) . (2 ^) . a000005'


CROSSREFS



KEYWORD

nonn,easy


AUTHOR



STATUS

approved



