OFFSET
1,3
LINKS
D. Mondot, Table of n, a(n) for n=1..32699
MATHEMATICA
Module[{nn=1500, t21}, t21=Table[{n, IntegerDigits[21^n]}, {n, 0, nn}]; Table[SelectFirst[ t21, IntegerDigits[k]==Take[#[[2]], IntegerLength[k]]&], {k, 80}]][[;; , 1]]//Quiet (* Harvey P. Dale, May 14 2023 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Daniel Mondot, Sep 18 2010
STATUS
approved