OFFSET
0,2
MATHEMATICA
a = {}; Do[k = 0; While[ Count[ IntegerDigits[7^k], 0] != n, k++ ]; a = Append[a, k], {n, 0, 50} ]; a
Module[{p7=DigitCount[#, 10, 0]&/@(7^Range[600]), nn=60}, Join[{0}, Flatten[ Table[ Position[p7, n, 1, 1], {n, nn}]]]] (* Harvey P. Dale, Apr 12 2022 *)
PROG
(PARI) A063606(n)=for(k=n, oo, #select(d->!d, digits(5^k))==n&&return(k)) \\ M. F. Hasler, Jun 14 2018
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Robert G. Wilson v, Aug 10 2001
STATUS
approved