OFFSET
2,1
EXAMPLE
a(9)=3 because 111111111 -> 151 -> 8 -> 15.
a(1) does not exist because 1 -> 1 and never reaches 15.
CROSSREFS
KEYWORD
less,nonn,base
AUTHOR
Jason Earls, Jun 01 2004
EXTENSIONS
More terms from David Wasserman, May 22 2007
STATUS
approved