OFFSET
1,5
COMMENTS
a(n) = number of terms of A269861 <= n.
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..10000
FORMULA
MATHEMATICA
f[n_] := (Times @@ Power[If[# == 1, 1, NextPrime@ #] & /@ First@ #, Last@ #] + 1)/2 &@ Transpose@ FactorInteger@ n; s = Select[Range@ 150, Xor[EvenQ@ f@ #, EvenQ@ #] &]; Table[Count[s, k_ /; k <= n], {n, 87}] (* Michael De Vlieger, Mar 17 2016 *)
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Mar 16 2016
STATUS
approved