OFFSET
0,10
COMMENTS
Differs from the sequence A112345 which does not consider 1 as a perfect power.
LINKS
Vaclav Kotesovec, Table of n, a(n) for n = 0..10000
Eric Weisstein's World of Mathematics, Perfect Power
EXAMPLE
a(25) = 3 because we have [25], [16, 9] and [16, 8, 1].
MATHEMATICA
nmax = 100; CoefficientList[Series[(1 + x) Product[(1 + Boole[GCD @@ FactorInteger[k][[All, 2]] > 1] x^k), {k, 1, nmax}], {x, 0, nmax}], x]
PROG
(PARI) Vec((1 + x) * prod(k=1, 100, 1 + (gcd(factorint(k)[, 2])>1)*x^k) + O(x^101)) \\ Indranil Ghosh, Mar 21 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Mar 21 2017
STATUS
approved