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a(n)=((2^n+1)^n-(2^n-1)^n)/2
0

%I #2 Mar 31 2012 10:22:16

%S 1,8,193,16448,5253121,6447694208,30795721162753,576522325894105088,

%T 42502811563960266915841,12379542064132015743721023488,

%U 14278867426031486089248841370959873

%N a(n)=((2^n+1)^n-(2^n-1)^n)/2

%t Table[((2^x + 1)^x - (2^x - 1)^x)/2, {x, 1, 15}]

%K nonn

%O 1,2

%A _Artur Jasinski_, Feb 01 2010