A063568 5^a(n) is the smallest positive power of 5 having n in its decimal representation.

8, 3, 2, 5, 11, 1, 4, 7, 7, 8, 14, 23, 3, 30, 12, 6, 20, 15, 22, 9, 13, 33, 13, 22, 12, 2, 18, 37, 11, 17, 15, 5, 19, 35, 19, 14, 20, 21, 18, 8, 12, 12, 37, 20, 12, 17, 18, 21, 11, 26, 23, 14, 16, 9, 30, 23, 6, 15, 16, 24, 24

Offset: 0

Author

Robert G. Wilson v, Aug 10 2001

Keywords

• base
• nonn

Links

• Harvey P. Dale, Table of n, a(n) for n = 0..1000

Crossrefs

Essentially the same as A062522.

Programs

Mathematica

a = {}; Do[k = 1; While[ StringPosition[ ToString[5^k], ToString[n]] == {}, k++ ]; a = Append[a, k], {n, 0, 60} ]; a
sp5[n_]:=Module[{k=1,idn=IntegerDigits[n]},While[SequenceCount[ IntegerDigits[ 5^k], idn] == 0,k++];k]; Array[sp5,70,0] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Aug 05 2019 *)