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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 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
LINKS
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
KEYWORD
base,nonn
AUTHOR
Robert G. Wilson v, Aug 10 2001
EXTENSIONS
a(0) corrected by Zak Seidov, Jun 14 2018
STATUS
approved

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Last modified June 18 22:34 EDT 2024. Contains 373487 sequences. (Running on oeis4.)