OFFSET
0,4
COMMENTS
a(n) = How many steps more are needed to reach zero when starting from k = 2*n + 1 than when starting from k = 2*n and repeatedly applying the map that replaces k by k - d(k)? [Here d(k) is the number of divisors of k (A000005)]. If it takes more steps when starting from 2n than from 2n+1, then a(n) is negative.
LINKS
Antti Karttunen, Table of n, a(n) for n = 0..10000
CROSSREFS
KEYWORD
sign
AUTHOR
Antti Karttunen, Oct 02 2015
STATUS
approved