A111407 a(n) = f(f(n+1)) - f(f(n)), where f(0) = 0 and f(m) = tau(m) = A000005(m) for m > 0.
1, 1, 0, 0, 0, 1, -1, 1, -1, 1, -1, 2, -2, 1, 0, -1, 0, 2, -2, 2, -1, 0, -1, 2, -2, 1, 0, 1, -2, 2, -2, 2, -1, 0, 0, 0, -1, 1, 0, 1, -2, 2, -2, 2, 0, -1, -1, 2, -2, 2, -1, 1, -2, 2, -1, 1, -1, 0, -1, 4, -4, 1, 1, -2, 1, 1, -2, 2, -1, 1, -2, 4, -4, 1, 1, 0, -1, 1, -2, 2, -2, 1, -1, 4, -3, 0, 0, 1, -2, 4, -3, 1, -1, 0, 0, 3, -4, 2, 0, -1, -1
Offset: 0
Keywords
Links
- Antti Karttunen, Table of n, a(n) for n = 0..20000
Programs
-
PARI
f = numdiv; a(n) = f(f(n+1)) - f(f(n)); concat([1], vector(166,n,a(n))) \\ Joerg Arndt, Jul 06 2013
-
PARI
f(n) = if(!n,n,numdiv(n)); A111407(n) = f(f(n+1)) - f(f(n)); \\ Antti Karttunen, Oct 07 2017
Extensions
Description clarified by Antti Karttunen, Oct 07 2017