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A063630
Smallest k such that 9^k has exactly n 4's in its decimal representation.
0
1, 5, 6, 10, 30, 29, 43, 45, 36, 73, 75, 92, 68, 116, 102, 85, 98, 141, 166, 151, 109, 154, 172, 196, 175, 176, 217, 244, 245, 207, 275, 226, 242, 289, 269, 263, 297, 261, 326, 296, 355, 335, 369, 336, 412, 414, 360, 458, 394, 457, 404
OFFSET
0,2
MATHEMATICA
a = {}; Do[k = 1; While[ Count[ IntegerDigits[9^k], 4] != n, k++ ]; a = Append[a, k], {n, 0, 50} ]; a
With[{ns=9^Range[500]}, Log[9, #]&/@Flatten[Table[Select[ns, Count[ IntegerDigits[#], 4]==n&, 1], {n, 0, 50}]]] (* Harvey P. Dale, Oct 20 2011 *)
CROSSREFS
Sequence in context: A018834 A029943 A356760 * A342127 A119102 A162015
KEYWORD
base,nonn
AUTHOR
Robert G. Wilson v, Aug 10 2001
EXTENSIONS
Name corrected by Jon E. Schoenfield, Jun 26 2018
STATUS
approved