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a(n) = (2*n^2)^n.
2

%I #13 Sep 08 2022 08:45:41

%S 1,2,64,5832,1048576,312500000,139314069504,86812553324672,

%T 72057594037927936,76848453272063549952,102400000000000000000000,

%U 166712830744247830760081408,325619086145088897570576531456

%N a(n) = (2*n^2)^n.

%C Central terms of the triangle in A155955;

%H G. C. Greubel, <a href="/A155957/b155957.txt">Table of n, a(n) for n = 0..200</a>

%F a(n) = A062206(n)*A000079(n).

%F a(n) = n! * [x^n] 1/(1 + LambertW(-2*n*x)). - _Ilya Gutkovskiy_, Oct 03 2017

%t Table[If[n==0,1,(2*n^2)^n], {n, 0, 30}] (* _G. C. Greubel_, Sep 14 2018 *)

%o (PARI) vector(30, n, n--; (2*n^2)^n) \\ _G. C. Greubel_, Sep 14 2018

%o (Magma) [(2*n^2)^n: n in [0..30]]; // _G. C. Greubel_, Sep 14 2018

%Y Cf. A000079, A062206, A155955.

%K nonn

%O 0,2

%A _Reinhard Zumkeller_, Jan 31 2009