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A304326
Number of ways to write n as a product of a number that is not a perfect power and a squarefree number.
11
0, 1, 1, 1, 1, 3, 1, 0, 1, 3, 1, 3, 1, 3, 3, 0, 1, 3, 1, 3, 3, 3, 1, 2, 1, 3, 0, 3, 1, 7, 1, 0, 3, 3, 3, 3, 1, 3, 3, 2, 1, 7, 1, 3, 3, 3, 1, 2, 1, 3, 3, 3, 1, 2, 3, 2, 3, 3, 1, 7, 1, 3, 3, 0, 3, 7, 1, 3, 3, 7, 1, 3, 1, 3, 3, 3, 3, 7, 1, 2, 0, 3, 1, 7, 3, 3, 3, 2, 1
OFFSET
1,6
LINKS
EXAMPLE
The a(180) = 7 ways are (6*30), (12*15), (18*10), (30*6), (60*3), (90*2), (180*1).
MATHEMATICA
radQ[n_]:=And[n>1, GCD@@FactorInteger[n][[All, 2]]===1];
Table[Length[Select[Divisors[n], radQ[#]&&SquareFreeQ[n/#]&]], {n, 100}]
PROG
(PARI) a(n)={sumdiv(n, d, d<>1 && !ispower(d) && issquarefree(n/d))} \\ Andrew Howroyd, Aug 26 2018
CROSSREFS
Positions of zeros are A246549. Range appears to be A075427.
Sequence in context: A122779 A120323 A320476 * A099905 A268441 A264435
KEYWORD
nonn
AUTHOR
Gus Wiseman, May 10 2018
STATUS
approved