OFFSET
0,18
COMMENTS
a(10^n) = 0 for all n > 0.
The PARI code uses that, if sumdigit(n^k) <> n until sumdigits(n^k) > 2n for the first time, then sumdigits(n^k) <> n for all larger k. This might not be true for all n, although statistically sumdigits(n^k) ~ 4.5*log_10(n')*k within a few % (n' = n with trailing 0's removed), when k is not too small. - M. F. Hasler, May 18 2017
LINKS
Hans Havermann, Table of n, a(n) for n = 0..10000
PROG
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Derek Orr, Sep 25 2014
EXTENSIONS
Data corrected (initial 1 removed, terminal 0 added) by Hans Havermann, Jul 13 2018
STATUS
approved