A063587 Smallest k such that 5^k has exactly n 2's in its decimal representation.

1, 2, 11, 13, 28, 25, 46, 53, 64, 66, 85, 100, 97, 115, 116, 148, 145, 107, 139, 184, 175, 209, 199, 274, 276, 251, 232, 244, 342, 250, 329, 339, 312, 375, 354, 332, 394, 351, 419, 362, 453, 415, 484, 517, 509, 468, 550, 541, 496, 522, 504

Offset

0,2

Links

Robert Israel, Table of n, a(n) for n = 0..5000

Maple

N:= 100:
V:= Array(0..N): count:= 0:
for k from 1 while count < N+1 do
  v:= numboccur(2, convert(5^k, base, 10));
  if v <= N and V[v] = 0 then count:= count+1; V[v]:= k;
  fi
od:
seq(V[i], i=0..N); # Robert Israel, Aug 02 2019

Mathematica

a = {}; Do[k = 1; While[ Count[ IntegerDigits[5^k], 2] != n, k++ ]; a = Append[a, k], {n, 0, 50} ]; a

Crossrefs

Sequence in context: A247338 A154742 A257329 * A038972 A242776 A373824

Adjacent sequences: A063584 A063585 A063586 * A063588 A063589 A063590

Keyword

base,nonn

Author

Robert G. Wilson v, Aug 10 2001

Extensions

Name corrected by Jon E. Schoenfield, Jun 26 2018

Status

approved