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%I #9 Jun 18 2015 14:17:00
%S 8,16,76,41,1162,973,6838,25265,81782,456686,279270,1727606,6030753,
%T 23157026
%N Least power of 2 having exactly n consecutive 5's in its decimal representation.
%C No more terms < 28*10^6.
%H Popular Computing (Calabasas, CA), <a href="/A094776/a094776.jpg">Two Tables</a>, Vol. 1, (No. 9, Dec 1973), page PC9-16.
%e a(3)=76 because 2^76(i.e. 75557863725914323419136) is the smallest power of 2 to contain a run of 3 consecutive fives in its decimal form.
%t a = ""; Do[ a = StringJoin[a, "5"]; b = StringJoin[a, "5"]; k = 1; While[ StringPosition[ ToString[2^k], a] == {} || StringPosition[ ToString[2^k], b] != {}, k++ ]; Print[k], {n, 1, 10} ]
%K more,nonn,base
%O 1,1
%A _Shyam Sunder Gupta_, Aug 26 2007
%E 2 more terms from _Sean A. Irvine_, Jul 19 2010
%E a(13)-a(14) from _Lars Blomberg_, Jan 24 2013
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