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a(n) = !n*n!.
5

%I #17 Dec 15 2017 17:35:03

%S 0,1,4,24,240,4080,110880,4404960,238452480,16777393920,1484592883200,

%T 161180605555200,21054378333542400,3256459844769331200,

%U 588451470437627596800,122827588904844375552000

%N a(n) = !n*n!.

%H Harry J. Smith, <a href="/A061640/b061640.txt">Table of n, a(n) for n = 0..100</a>

%F a(n) = A000142(n)*A003422(n).

%p a:=n->sum((n+1)!*j!,j=0..n): seq(a(n), n=-1..15); # _Zerinvary Lajos_, Jan 08 2007

%t Table[n!*Sum[i!, {i, 0, n - 1}], {n, 0, 16}] (* _Olivier GĂ©rard_, Sep 28 2012 *)

%o (PARI) { for (n=0, 100, L=sum(k=0, n-1, k!); write("b061640.txt", n " ", L*n!) ) } \\ _Harry J. Smith_, Jul 25 2009

%Y Cf. A000142, A003422.

%K easy,nonn

%O 0,3

%A _Jason Earls_, Jun 13 2001

%E More terms from Larry Reeves (larryr(AT)acm.org), Jun 19 2001