A063616 Smallest k >= 0 such that 8^k has exactly n 0's in its decimal representation.

0, 4, 14, 23, 42, 33, 35, 34, 63, 66, 87, 116, 84, 101, 126, 164, 128, 102, 135, 143, 149, 155, 203, 224, 186, 204, 210, 237, 261, 218, 219, 286, 257, 266, 361, 355, 336, 302, 374, 339, 371, 398, 340, 409, 348, 388, 494, 436, 407, 406, 439

Offset

0,2

Links

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

Mathematica

a = {}; Do[k = 0; While[ Count[ IntegerDigits[8^k], 0] != n, k++ ]; a = Append[a, k], {n, 0, 50} ]; a

Prog

(PARI) A063616(n)=for(k=0, oo, #select(d->!d, digits(8^k))==n&&return(k)) \\ M. F. Hasler, Jun 14 2018

Crossrefs

Cf. A031146 (analog for 2^k), A063555 (analog for 3^k), A063575 (analog for 4^k), A063585 (for 5^k), A063596 (analog for 6^k), A063606 (analog for 7^k).

Sequence in context: A317734 A154046 A000054 * A213399 A031254 A031224

Adjacent sequences: A063613 A063614 A063615 * A063617 A063618 A063619

Keyword

base,nonn

Author

Robert G. Wilson v, Aug 10 2001

Extensions

a(0) changed to 0 (as in A031146, A063555, ...) and better title from M. F. Hasler, Jun 14 2018

Status

approved