OFFSET
0,50
EXAMPLE
tri(49)=1225, so a(49)=2 and tri(651)=212226, so a(651)=4.
MATHEMATICA
DigitCount[#, 10, 2]&/@Accumulate[Range[0, 120]] (* Harvey P. Dale, Jan 02 2016 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Jason Earls, Jul 08 2003
STATUS
approved