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A063584 Smallest k such that 4^k has exactly n 9's in its decimal representation. 1
1, 6, 17, 16, 45, 56, 46, 70, 77, 86, 93, 122, 127, 173, 171, 166, 172, 214, 178, 217, 253, 300, 265, 238, 286, 266, 298, 364, 331, 343, 368, 365, 446, 447, 425, 423, 396, 483, 480, 506, 576, 575, 594, 592, 678, 579, 671, 621, 539, 664, 620 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

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

MATHEMATICA

a = {}; Do[k = 1; While[ Count[ IntegerDigits[4^k], 9] != n, k++ ]; a = Append[a, k], {n, 0, 50} ]; a

With[{n9s=DigitCount[#, 10, 9]&/@(4^Range[700])}, Flatten[Table[ Position[ n9s, n, {1}, 1], {n, 0, 50}]]] (* Harvey P. Dale, Oct 20 2013 *)

CROSSREFS

Sequence in context: A200871 A112366 A095421 * A019296 A035484 A277684

Adjacent sequences:  A063581 A063582 A063583 * A063585 A063586 A063587

KEYWORD

base,nonn

AUTHOR

Robert G. Wilson v, Aug 10 2001

EXTENSIONS

Name corrected by Jon E. Schoenfield, Jun 26 2018

STATUS

approved

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Last modified August 8 14:36 EDT 2020. Contains 336298 sequences. (Running on oeis4.)