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Partial sums of A003149.
0

%I #12 Jun 28 2017 19:24:38

%S 1,3,8,24,88,400,2212,14500,110116,951076,9205156,98646436,1159016356,

%T 14808626596,204358994596,3028436306596,47955883346596,

%U 807990334802596,14430691329362596,272302801683794596,5412861968581970596

%N Partial sums of A003149.

%C Total resistance of a circuit whose n-th component is between opposite corners of an n-dimensional hypercube of unit resistors, multiplied by n!. The only prime in the sequence is 3. The subsequence of squares begins 1, 400, 9205156 = 2^2 * 37^2 * 41^2.

%F a(n) = Sum_{i=0..n} Sum_{k=0..i} k!*(i-k)!.

%e a(5) = 1 + 2 + 5 + 16 + 64 + 312 = 400 = 2^4 * 5^2.

%Y Cf. A003149, A046825, A046878, A046879, A052186, A006932, A145878.

%K nonn,easy

%O 0,2

%A _Jonathan Vos Post_, Nov 30 2010

%E Offset set to 0 by _Alois P. Heinz_, Jun 28 2017