

A063555


Smallest k such that 3^k has exactly n 0's in its decimal representation.


12



0, 10, 22, 21, 35, 57, 55, 54, 107, 137, 126, 170, 188, 159, 191, 225, 259, 297, 262, 253, 340, 296, 380, 369, 403, 395, 383, 407, 429, 514, 446, 486, 431, 545, 589, 510, 546, 542, 666, 733, 540, 621, 709, 715, 549, 694, 804, 820, 847, 865, 710
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OFFSET

0,2


LINKS

Robert Israel, Table of n, a(n) for n = 0..2000


MAPLE

N:= 100: # to get a(0)..a(N)
A:= Array(0..N, 1):
p:= 1: A[0]:= 0:
count:= 1:
for k from 1 while count <= N do
p:= 3*p;
m:= numboccur(0, convert(p, base, 10));
if m <= N and A[m] < 0 then A[m]:= k; count:= count+1 fi
od:
seq(A[i], i=0..N); # Robert Israel, Dec 21 2016


MATHEMATICA

a = {}; Do[k = 1; While[ Count[ IntegerDigits[3^k], 0] != n, k++ ]; a = Append[a, k], {n, 0, 50} ]; a
Module[{l3=Table[{n, DigitCount[3^n, 10, 0]}, {n, 900}]}, Transpose[Table[ SelectFirst[ l3, #[[2]]==i&], {i, 0, 50}]][[1]]] (* Harvey P. Dale, Dec 08 2014 *)


PROG

(PARI) A063555(n)=for(k=0, oo, #select(d>!d, digits(3^k))==n&&return(k)) \\ M. F. Hasler, Jun 14 2018


CROSSREFS

Cf. A000244.
Cf. A031146 (analog for 2^k), A063575 (analog for 4^k).
Sequence in context: A226789 A110367 A104865 * A228010 A303745 A303746
Adjacent sequences: A063552 A063553 A063554 * A063556 A063557 A063558


KEYWORD

base,nonn


AUTHOR

Robert G. Wilson v, Aug 10 2001


EXTENSIONS

a(0) corrected by Zak Seidov, Jun 14 2018


STATUS

approved



