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A063429 Smallest k such that 2^k has exactly n 3's in its decimal representation. 9
1, 5, 49, 25, 35, 109, 96, 128, 135, 169, 182, 156, 208, 302, 310, 277, 221, 300, 346, 498, 387, 502, 563, 507, 503, 611, 550, 585, 615, 681, 731, 817, 819, 835, 779, 860, 849, 840, 879, 997, 1016, 925, 1066, 1161, 1117, 1186, 1282, 1090, 1293, 1251, 1444 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Harry J. Smith, Table of n, a(n) for n = 0..150

MATHEMATICA

a = {}; Do[k = 1; While[ Count[ IntegerDigits[2^k], 3] != n, k++ ]; a = Append[a, k], {n, 0, 50} ]; a

PROG

(PARI) a(n)={my(k=1); while(n<>#select(d->d==3, digits(2^k)), k++); k} \\ Harry J. Smith, Aug 20 2009, Andrew Howroyd, Jun 26 2018

CROSSREFS

Cf. A063115, A063426, A063430, A063526, A063540, A063552, A063553, A063554.

Sequence in context: A108207 A127091 A224510 * A297856 A298091 A298053

Adjacent sequences:  A063426 A063427 A063428 * A063430 A063431 A063432

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 December 15 22:02 EST 2019. Contains 330012 sequences. (Running on oeis4.)