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 A174992 #13 Mar 12 2014 16:37:15
%S A174992 0,0,1,4,19,107,682,4915,39871,361138,3621531,39884367,478847750,
%T A174992 6226248403,87174202427,1307651621142,20922657286067,355686620215179,
%U A174992 6402368573492818,121645066483568099,2432901775271051559,51090940513901948778
%N A174992 a(n) = n! - A000800(n).
%t A174992 a = Table[n! - Sum[(
%t A174992 Eulerian[n - j, j]), {j, 0, Floor[n/2]}], {n, 0, 30}]
%Y A174992 Cf. A000800, A008292.
%K A174992 nonn
%O A174992 0,4
%A A174992 _Roger L. Bagula_, Dec 02 2010
%E A174992 Definition corrected by _Roger L. Bagula_, Dec 03 2010