A063590 Smallest k such that 5^k has exactly n 5's in its decimal representation.

1, 6, 14, 27, 30, 41, 65, 66, 54, 83, 73, 109, 102, 112, 118, 106, 187, 159, 175, 204, 209, 174, 222, 278, 234, 327, 266, 300, 369, 318, 310, 339, 350, 377, 301, 357, 426, 411, 446, 421, 434, 452, 490, 525, 494, 521, 554, 543, 514, 503

Offset

1,2

Links

Harvey P. Dale, Table of n, a(n) for n = 1..500

Mathematica

a = {}; Do[k = 1; While[ Count[ IntegerDigits[5^k], 5] != n, k++ ]; a = Append[a, k], {n, 1, 50} ]; a
With[{tbl=Table[{k, DigitCount[5^k, 10, 5]}, {k, 600}]}, Table[SelectFirst[tbl, #[[2]]==n&], {n, 50}]][[;; , 1]] (* This program is many times more efficient than the first Mathematica program above. *) (* Harvey P. Dale, Dec 13 2024 *)

Crossrefs

Sequence in context: A093776 A107317 A071776 * A349723 A378230 A128806

Adjacent sequences: A063587 A063588 A063589 * A063591 A063592 A063593

Keyword

base,nonn

Author

Robert G. Wilson v, Aug 10 2001

Extensions

Name corrected by Jon E. Schoenfield, Jun 26 2018

Status

approved