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%I #10 Aug 02 2019 08:41:00
%S 1,2,11,13,28,25,46,53,64,66,85,100,97,115,116,148,145,107,139,184,
%T 175,209,199,274,276,251,232,244,342,250,329,339,312,375,354,332,394,
%U 351,419,362,453,415,484,517,509,468,550,541,496,522,504
%N Smallest k such that 5^k has exactly n 2's in its decimal representation.
%H Robert Israel, <a href="/A063587/b063587.txt">Table of n, a(n) for n = 0..5000</a>
%p N:= 100:
%p V:= Array(0..N): count:= 0:
%p for k from 1 while count < N+1 do
%p v:= numboccur(2, convert(5^k,base,10));
%p if v <= N and V[v] = 0 then count:= count+1; V[v]:= k;
%p fi
%p od:
%p seq(V[i],i=0..N); # _Robert Israel_, Aug 02 2019
%t a = {}; Do[k = 1; While[ Count[ IntegerDigits[5^k], 2] != n, k++ ]; a = Append[a, k], {n, 0, 50} ]; a
%K base,nonn
%O 0,2
%A _Robert G. Wilson v_, Aug 10 2001
%E Name corrected by _Jon E. Schoenfield_, Jun 26 2018