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 A204912 #8 Mar 30 2012 18:58:08
%S A204912 1,2,1,7,6,5,14,13,12,7,47,46,45,40,33,104,103,102,97,90,57,383,382,
%T A204912 381,376,369,336,279,944,943,942,937,930,897,840,561,3839,3838,3837,
%U A204912 3832,3825,3792,3735,3456,2895,10394,10393,10392,10387,10380
%N A204912 Ordered differences of double factorials.
%C A204912 For a guide to related sequences, see A204892.
%C A204912 As a triangle with rows {1}, {2,1}, {7,6,5}, ..., evidently the first diagonal is A007911 = {1,1,5,7,33,57,279,...} (up to an offset). - L. Edson Jeffery, Jan 24 2012
%e A204912 a(1)=2!!-1!!=2-1=1
%e A204912 a(2)=3!!-1!!=3-1=2
%e A204912 a(3)=3!!-2!!=3-2=1
%e A204912 a(4)=4!!-1!!=8-1=7
%e A204912 a(5)=4!!-2!!=8-2=6
%t A204912 (See the program at A204982.)
%Y A204912 Cf. A204982, A204892.
%Y A204912 Cf. A007911.
%K A204912 nonn
%O A204912 1,2
%A A204912 _Clark Kimberling_, Jan 22 2012