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A063587
Smallest k such that 5^k has exactly n 2's in its decimal representation.
1
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
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
KEYWORD
base,nonn
AUTHOR
Robert G. Wilson v, Aug 10 2001
EXTENSIONS
Name corrected by Jon E. Schoenfield, Jun 26 2018
STATUS
approved