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Smallest k such that 8^k has exactly n 2's in its decimal representation.
0

%I #8 Jun 26 2018 19:09:33

%S 1,3,6,17,24,31,27,41,61,59,58,87,84,123,99,89,138,116,110,189,164,

%T 162,150,156,184,197,235,234,263,277,244,216,316,268,343,295,356,270,

%U 329,325,321,334,393,452,328,375,425,462,392,469,388

%N Smallest k such that 8^k has exactly n 2's in its decimal representation.

%t a = {}; Do[k = 1; While[ Count[ IntegerDigits[8^k], 2] != n, k++ ]; a = Append[a, k], {n, 0, 50} ]; a

%t With[{twos=Table[DigitCount[8^n,10,2],{n,500}]},Flatten[Table[ Position[ twos, k,{1},1],{k,0,60}]]] (* _Harvey P. Dale_, Jul 18 2015 *)

%K base,nonn

%O 0,2

%A _Robert G. Wilson v_, Aug 10 2001

%E Name corrected by _Jon E. Schoenfield_, Jun 26 2018