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Least positive integer x such that 2*x^n>(x+3)^n.
2

%I #5 Jun 24 2014 01:08:33

%S 8,12,16,21,25,29,34,38,42,47,51,55,60,64,68,73,77,81,86,90,94,99,103,

%T 107,112,116,120,125,129,133,138,142,146,150,155,159,163,168,172,176,

%U 181,185,189,194,198,202,207,211,215,220,224,228,233,237,241,246,250

%N Least positive integer x such that 2*x^n>(x+3)^n.

%F a(n) = ceiling(3/(2^(1/n)-1)). For most n, a(n) = floor(3n/log(2)-1/2), but there are exceptions, starting with n=32 and n=52113.

%e a(2)=8 as 7^2=49, 8^2=64, 10^2=100 and 11^2=121.

%o (PARI) for (n=2,50, x=2; while (2*x^n<=((x+3)^n),x++); print1(x","))

%Y Cf. A078607, A078608.

%K nonn

%O 2,1

%A _Jon Perry_, Dec 09 2002

%E Edited by _Dean Hickerson_, Dec 17 2002