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a(n) = n^n * (n-1).
0

%I #10 Jan 16 2015 19:19:29

%S 0,4,54,768,12500,233280,4941258,117440512,3099363912,90000000000,

%T 2853116706110,98077104930816,3634501279107036,144456088732254208,

%U 6130514465332031250,276701161105643274240,13235844190181388226832

%N a(n) = n^n * (n-1).

%H Milan Janjic, <a href="http://www.pmfbl.org/janjic/">Enumerative Formulas for Some Functions on Finite Sets</a>

%F E.g.f.: -(1 + 3*LambertW(-x) + LambertW(-x)^2)/(1+LambertW(-x))^3. - _Vladeta Jovovic_, Dec 12 2003

%t f[n_]:=(n^(n+1)-n^n); lst={};Do[AppendTo[lst,f[n]],{n,5!}];lst (* _Vladimir Joseph Stephan Orlovsky_, Feb 07 2010 *)

%o (PARI) g(n) = for(x=1,n,print1(x^x*(x-1)","))

%K easy,nonn

%O 1,2

%A _Cino Hilliard_, Dec 09 2003

%E More terms from _Vladeta Jovovic_, Dec 12 2003