OFFSET
1,7
COMMENTS
It might be more natural to define the initial terms as a(0) = a(1) = 0 for the sake of recurrence. - Antti Karttunen, Oct 01 2018
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
Colin Defant, Python program
PROG
(Python) See Defant link. Enter m=4, as well as starting and ending values of n. The third string of numbers will be this sequence.
(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
A241665(n) = { my(s=(1==n)); while(n>1, n = A241663(n); s++); (s); }; \\ Antti Karttunen, Oct 01 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Colin Defant, Apr 26 2014
EXTENSIONS
More terms from Alois P. Heinz, Apr 30 2014
Terms a(88) .. a(105) from Antti Karttunen, Oct 01 2018
STATUS
approved