This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A061640 #17 Dec 15 2017 17:35:03
%S A061640 0,1,4,24,240,4080,110880,4404960,238452480,16777393920,1484592883200,
%T A061640 161180605555200,21054378333542400,3256459844769331200,
%U A061640 588451470437627596800,122827588904844375552000
%N A061640 a(n) = !n*n!.
%H A061640 Harry J. Smith, <a href="/A061640/b061640.txt">Table of n, a(n) for n = 0..100</a>
%F A061640 a(n) = A000142(n)*A003422(n).
%p A061640 a:=n->sum((n+1)!*j!,j=0..n): seq(a(n), n=-1..15); # _Zerinvary Lajos_, Jan 08 2007
%t A061640 Table[n!*Sum[i!, {i, 0, n - 1}], {n, 0, 16}] (* _Olivier Gérard_, Sep 28 2012 *)
%o A061640 (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 A061640 Cf. A000142, A003422.
%K A061640 easy,nonn
%O A061640 0,3
%A A061640 _Jason Earls_, Jun 13 2001
%E A061640 More terms from Larry Reeves (larryr(AT)acm.org), Jun 19 2001