A055867 Fourth column of triangle A055864.
0, 0, 0, 64, 750, 10584, 175616, 3359232, 72900000, 1771561000, 47692136448, 1409582685888, 45392319784448, 1582328671875000, 59373627899904000, 2386420683693101056, 102303226385042448384, 4659806991485780193672
Offset: 1
Programs
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Maple
A055867:=n->n^3*(n+1)^(n-4): 0,0,0,seq(A055867(n), n=4..30); # Wesley Ivan Hurt, Jan 27 2017
Formula
a(i)=0 for i=1, 2, 3; a(n) = n^3*(n+1)^(n-4), n >= 4.
E.g.f.: (9*W(-x)^2-14*W(-x)^3+3*W(-x)^4-9*x^2-32*x^3-81*x^4)/(72*x), W(x) principal branch of Lambert's function.