A063623 Smallest k such that 8^k has exactly n 7's in its decimal representation.

1, 5, 9, 8, 44, 25, 51, 59, 61, 74, 76, 79, 99, 94, 120, 117, 115, 143, 163, 148, 139, 194, 178, 211, 203, 157, 158, 272, 218, 217, 270, 285, 307, 337, 314, 334, 260, 322, 299, 354, 344, 479, 327, 385, 401, 389, 408, 455, 445, 430, 400

Offset

0,2

Links

Table of n, a(n) for n=0..50.

Mathematica

a = {}; Do[k = 1; While[ Count[ IntegerDigits[8^k], 7] != n, k++ ]; a = Append[a, k], {n, 0, 50} ]; a
With[{n8=Table[DigitCount[8^n, 10, 7], {n, 0, 500}]}, Join[{1}, Flatten[ Table[ Position[ n8, i, {1}, 1], {i, 50}]]-1]] (* Harvey P. Dale, Apr 10 2016 *)

Crossrefs

Sequence in context: A244249 A353602 A123600 * A085566 A076390 A321632

Adjacent sequences: A063620 A063621 A063622 * A063624 A063625 A063626

Keyword

base,nonn

Author

Robert G. Wilson v, Aug 10 2001

Extensions

Name corrected by Jon E. Schoenfield, Jun 26 2018

Status

approved