A063578 Smallest k such that 4^k has exactly n 3's in its decimal representation.

1, 7, 26, 43, 38, 57, 48, 64, 81, 92, 91, 78, 104, 151, 155, 143, 162, 150, 173, 249, 267, 251, 339, 282, 333, 325, 275, 378, 345, 428, 415, 429, 473, 463, 411, 430, 513, 420, 507, 546, 508, 489, 533, 603, 566, 593, 641, 545, 707, 638, 722

Offset

0,2

Links

Robert Israel, Table of n, a(n) for n = 0..1000

Maple

N:= 100: # to get a(0) to a(N)
A:= Array(0..N):
count:= 0:
for n from 1 while count < N+1 do
   v:= numboccur(3, convert(4^n, base, 10));
   if v <= N and A[v] = 0 then
     count:= count+1;
     A[v]:= n;
   fi
od:
seq(A[i], i=0..N); # Robert Israel, Feb 24 2016

Mathematica

a = {}; Do[k = 1; While[ Count[ IntegerDigits[4^k], 3] != n, k++ ]; a = Append[a, k], {n, 0, 50} ]; a

Crossrefs

Cf. A063576, A063577, A063579, A063580, A063581, A063582, A063583, A063584.

Sequence in context: A103267 A125972 A063153 * A063159 A274268 A059376

Adjacent sequences: A063575 A063576 A063577 * A063579 A063580 A063581

Keyword

base,nonn

Author

Robert G. Wilson v, Aug 10 2001

Extensions

Name corrected by Jon E. Schoenfield, Jun 26 2018

Status

approved