OFFSET
0,2
MATHEMATICA
a = {}; Do[k = 1; While[ Count[ IntegerDigits[4^k], 8] != n, k++ ]; a = Append[a, k], {n, 0, 50} ]; a
With[{tbl=Table[{n, DigitCount[4^n, 10, 8]}, {n, 1000}]}, Table[SelectFirst[tbl, #[[2]]==k&], {k, 0, 50}]][[;; , 1]] (* Harvey P. Dale, Oct 24 2023 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Robert G. Wilson v, Aug 10 2001
EXTENSIONS
Name corrected by Jon E. Schoenfield, Jun 26 2018
STATUS
approved