A063603 Smallest k such that 6^k has exactly n 7's in its decimal representation.

1, 7, 9, 5, 26, 35, 30, 48, 72, 60, 65, 77, 100, 127, 146, 130, 152, 150, 155, 230, 205, 192, 201, 234, 274, 255, 279, 286, 249, 297, 292, 321, 312, 331, 225, 335, 396, 342, 345, 405, 370, 385, 445, 461, 503, 442, 480, 469, 473, 518, 510

Offset

0,2

Links

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

Mathematica

a = {}; Do[k = 1; While[ Count[ IntegerDigits[6^k], 7] != n, k++ ]; a = Append[a, k], {n, 0, 50} ]; a
Join[{1}, Flatten[With[{p6=6^Range[650]}, Table[First[Position[p6, _?(Count[ IntegerDigits[#], 7]==n&)]], {n, 55}]]]] (* Harvey P. Dale, Oct 03 2011 *)

Crossrefs

Sequence in context: A215736 A132715 A154910 * A218360 A020788 A198921

Adjacent sequences: A063600 A063601 A063602 * A063604 A063605 A063606

Keyword

base,nonn

Author

Robert G. Wilson v, Aug 10 2001

Extensions

Name corrected by Jon E. Schoenfield, Jun 26 2018

Offset corrected by Sean A. Irvine, Jul 23 2023

Status

approved