OFFSET
1,2
COMMENTS
FORMULA
a(n) = A053830(9^k + n - 1) where k >= ceiling(log_9(n/8)). - R. J. Mathar, Dec 09 2010
MATHEMATICA
Table[1 + Plus@@IntegerDigits[n - 1, 9], {n, 90}] (* Vincenzo Librandi, Jul 01 2019 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Omar E. Pol, Feb 23 2010
STATUS
approved