1,18

Harvey P. Dale, Table of n, a(n) for n = 1..1000

cfnsQ[n_]:=Module[{f=FactorInteger[n][[All, 2]]}, Max[f]<3&&Count[f, 2] == 1&&!IntegerQ[Sqrt[n]]]; Accumulate[Table[If[cfnsQ[n], 1, 0], {n, 100}]] (* Harvey P. Dale, May 24 2017 *)

Cf. A072358, A060431.

Sequence in context: A140474 A091195 A280617 * A131981 A257244 A130147

Adjacent sequences: A072372 A072373 A072374 * A072376 A072377 A072378

nonn

Reinhard Zumkeller, Jul 19 2002

approved