OFFSET
1,4
COMMENTS
Taking every ninth term gives the same sequence: (and similarly for all higher powers of 9 as well): a(n) = a(9*n).
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..6561
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Aug 01 2009
EXTENSIONS
Name corrected by Kevin Ryde, Aug 29 2020
STATUS
approved