OFFSET
1,7
COMMENTS
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..65537
C. Defant, On Arithmetic Functions Related to Iterates of the Schemmel Totient Functions, J. Int. Seq. 18 (2015) # 15.2.1
MATHEMATICA
L[n_, m_] :=
If[Min[Select[Divisors[n], PrimeQ]] <= m, 0,
n*Times @@ (1 - m/(Select[Divisors[n], PrimeQ]))]
a[0]:=0
a[5]:=1
a[n_]:=L[n, 4]+a[L[n, 4]]
PROG
(PARI)
A241663(n) = {my(f = factor(n)); prod(i=1, #f~, if ((f[i, 1] == 2) || (f[i, 1] == 3), 0, f[i, 1]^(f[i, 2]-1)*(f[i, 1]-4))); } \\ From A241663
A241668(n) = { my(s=(1==n)); while(n>1, n = A241663(n); s += n); (s); }; \\ Antti Karttunen, Oct 01 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Colin Defant, Apr 26 2014
STATUS
approved