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A131549 Least power of 3 having exactly n consecutive 4's in its decimal representation. 1

%I

%S 5,12,55,308,510,2340,7286,9670,125406,222961,847169,639226,6250771,

%T 14929721

%N Least power of 3 having exactly n consecutive 4's in its decimal representation.

%C No more terms < 2*10^7.

%e a(3)=55 because 3^55(i.e. 174449211009120179071170507) is the smallest power of 3 to contain a run of 3 consecutive fours in its decimal form.

%t a = ""; Do[ a = StringJoin[a, "4"]; b = StringJoin[a, "4"]; k = 1; While[ StringPosition[ ToString[3^k], a] == {} || StringPosition[ ToString[3^k], b] != {}, k++ ]; Print[k], {n, 1, 10} ]

%K more,nonn,base

%O 1,1

%A _Shyam Sunder Gupta_, Aug 26 2007

%E a(11)-a(14) from _Lars Blomberg_, Feb 02 2013

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Last modified December 22 10:11 EST 2014. Contains 252339 sequences.