OFFSET

1,3

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..65537

MATHEMATICA

s[n_] := Boole[n > 1 && Length[(f = FactorInteger[n])] == 1 && (e = f[[;; , 2]]) == 2^IntegerExponent[e, 2]]; Accumulate @ Array[s, 100] (* Amiram Eldar, Nov 27 2020 *)

PROG

CROSSREFS

KEYWORD

nonn

AUTHOR

Antti Karttunen, Apr 16 2018

STATUS

approved