OFFSET
0,7
COMMENTS
Formally speaking, a(1) is not defined but letting a(1)=0 does not break any formula.
LINKS
Antti Karttunen, Table of n, a(n) for n = 0..16384
FORMULA
a(0) = a(1) = 0 and for n>=2, a(n) = 1 + max_{d|n, d>1} a((n-d)/d).
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Max Alekseyev, Nov 13 2009
STATUS
approved