OFFSET
1,2
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..16384
FORMULA
Multiplicative with a(p^e) = (p-A000035(p))^e.
Sum_{k=1..n} a(k) ~ c * n^2, where c = Pi^4/(210*zeta(3)) = (3/4) * A068468 = 0.385882... . - Amiram Eldar, Nov 10 2022
MATHEMATICA
Array[If[# == 1, 1, Apply[Times, FactorInteger[#] /. {p_Integer, e_Integer} :> If[p == 2, 2, p - 1]^e]] &, 85] (* Michael De Vlieger, Apr 15 2020 *)
PROG
(PARI) A333787(n) = { my(f=factor(n)); for(i=1, #f~, f[i, 1] -= (f[i, 1]%2)); factorback(f); };
CROSSREFS
KEYWORD
nonn,mult
AUTHOR
Antti Karttunen, Apr 07 2020
STATUS
approved