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A305632
Expansion of Product_{r = 1 or not a perfect power} 1/(1 + (-x)^r).
2
1, 1, 0, 1, 2, 2, 1, 2, 4, 3, 2, 4, 6, 5, 4, 7, 10, 8, 7, 11, 15, 13, 12, 17, 22, 19, 18, 25, 30, 28, 26, 35, 42, 39, 38, 49, 59, 56, 54, 69, 81, 77, 76, 94, 110, 105, 105, 127, 147, 141, 142, 171, 195, 189, 190, 227, 257, 250, 254, 299, 335, 328, 334, 390, 432
OFFSET
0,5
EXAMPLE
O.g.f.: 1/((1 - x)(1 + x^2)(1 - x^3)(1 - x^5)(1 + x^6)(1 - x^7)(1 + x^10)...).
MATHEMATICA
nn=20;
radQ[n_]:=Or[n==1, GCD@@FactorInteger[n][[All, 2]]==1];
ser=Product[1/(1+(-x)^p), {p, Select[Range[nn], radQ]}];
Table[SeriesCoefficient[ser, {x, 0, n}], {n, 0, nn}]
KEYWORD
nonn
AUTHOR
Gus Wiseman, Jun 07 2018
STATUS
approved