A063596 Least k >= 0 such that 6^k has exactly n 0's in its decimal representation.

0, 10, 9, 13, 19, 43, 56, 41, 94, 79, 113, 100, 88, 112, 124, 127, 138, 176, 144, 175, 174, 168, 170, 210, 245, 228, 182, 237, 287, 260, 312, 321, 294, 347, 389, 365, 401, 386, 390, 419, 460, 425, 438, 426, 488, 490, 520, 458, 489, 521, 513

Offset: 0

Author

Robert G. Wilson v, Aug 10 2001

Keywords

• base
• nonn

Crossrefs

Cf. A031146 (analog for 2^k), A063555 (for 3^k), A063575 (for 4^k), A063585 (for 5^k), A063606 (for 7^k), A063616 (for 8^k), A063626 (for 9^k).

Programs

Mathematica

a = {}; Do[k = 0; While[ Count[ IntegerDigits[6^k], 0] != n, k++ ]; a = Append[a, k], {n, 0, 50} ]; a
With[{pwr6=Table[{n,DigitCount[6^n,10,0]},{n,1000}]},Join[{0},Transpose[ Table[ SelectFirst[pwr6,#[[2]]==i&],{i,60}]][[1]]]] (* Harvey P. Dale, Dec 15 2014 *)

PARI

A063596(n)=for(k=0, oo, #select(d->!d, digits(6^k))==n&&return(k)) \\ M. F. Hasler, Jun 14 2018

Extensions

a(0) changed to 0 (as in A031146, A063555, ...) and better title from M. F. Hasler, Jun 14 2018