%I #4 Mar 31 2012 13:20:04

%S 0,0,0,36,400,5400,86436,1605632,34012224,810000000,21435888100,

%T 624333422592,19851622826256,684376513673216,25430282226562500,

%U 1013309916158361600,43104723599206637824,1949779138161985486848

%N Fourth column of triangle A055858.

%F a(i)=0, i=0, 1, 2; a(n)= (n^2)*(n+1)^(n-2), n >= 3.

%F E.g.f.: -x*(1+4*x)/2 + (W(-x)^2)*(1-W(-x))/((1+W(-x))*x*2), W(x) principal branch of Lambert's function.

%Y a(n)=A055858(n, 3). Cf. A000312, A000169, A055860, A055861.

%K nonn,easy

%O 0,4

%A _Wolfdieter Lang_ Jun 20 2000