A063614 Smallest k such that 7^k has exactly n 8's in its decimal representation.

1, 5, 12, 19, 21, 22, 58, 51, 52, 65, 78, 79, 77, 123, 161, 148, 132, 131, 145, 141, 201, 154, 225, 155, 237, 281, 233, 248, 265, 293, 264, 279, 272, 287, 322, 261, 304, 382, 406, 424, 389, 381, 475, 414, 397, 458, 434, 483, 446, 541, 465

Offset

0,2

Links

Harvey P. Dale, Table of n, a(n) for n = 0..100

Mathematica

a = {}; Do[k = 1; While[ Count[ IntegerDigits[7^k], 8] != n, k++ ]; a = Append[a, k], {n, 0, 50} ]; a
Module[{nn=600, tk}, tk=Table[{k, DigitCount[7^k, 10, 8]}, {k, nn}]; Table[ SelectFirst[ tk, #[[2]]==n&], {n, 0, 50}]][[All, 1]] (* Harvey P. Dale, Dec 11 2022 *)

Crossrefs

Sequence in context: A174518 A109403 A093084 * A048928 A003328 A048926

Adjacent sequences: A063611 A063612 A063613 * A063615 A063616 A063617

Keyword

base,nonn

Author

Robert G. Wilson v, Aug 10 2001

Extensions

Name corrected by Jon E. Schoenfield, Jun 26 2018

Status

approved