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A063426 Smallest k such that 2^k has exactly n 2's in its decimal representation. 9
2, 1, 18, 43, 41, 93, 81, 107, 125, 177, 174, 196, 200, 197, 280, 265, 320, 348, 330, 481, 492, 486, 314, 449, 535, 509, 505, 616, 686, 742, 577, 598, 743, 788, 991, 885, 941, 810, 987, 934, 963, 970, 1165, 1018, 984, 1125, 928, 1279, 1126, 1232, 1164 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,1
LINKS
MATHEMATICA
a = {}; Do[k = 1; While[ Count[ IntegerDigits[2^k], 2] != n, k++ ]; a = Append[a, k], {n, 0, 50} ]; a
PROG
(PARI) a(n)={my(k=1); while(n<>#select(d->d==2, digits(2^k)), k++); k} \\ Harry J. Smith, Aug 23 2009, Andrew Howroyd, Jun 26 2018
CROSSREFS
Sequence in context: A089512 A300956 A089014 * A316195 A266010 A349960
KEYWORD
base,nonn
AUTHOR
Robert G. Wilson v, Aug 10 2001
EXTENSIONS
Name corrected by Jon E. Schoenfield, Jun 25 2018
STATUS
approved

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Last modified March 28 18:04 EDT 2024. Contains 371254 sequences. (Running on oeis4.)