OFFSET
1,5
EXAMPLE
n=21: numbers >21 and <=441=21^2 containing "21": {121, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 221, 321, 421} having size 14, therefore a(21)=14.
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Reinhard Zumkeller, Jun 10 2002
STATUS
approved