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 A092081 #10 Aug 29 2019 09:13:49 %S A092081 1,1,2,1,3,8,1,4,15,48,1,5,24,105,384,1,6,35,192,945,3840,1,7,48,315, %T A092081 1920,10395,46080,1,8,63,480,3465,23040,135135,645120,1,9,80,693,5760, %U A092081 45045,322560,2027025,10321920,1,10,99,960,9009,80640,675675,5160960 %N A092081 Triangle of certain double factorials. %C A092081 This is the rectangular array A(3;m,n) := (2*n+m)!!/m!!, m >= 0, n >= 0, read by SW-NE diagonals. For n!! see A006882 (double factorials). %H A092081 W. Lang, <a href="/A092081/a092081.txt">First 9 rows</a>. %F A092081 a(m, n)=(n+m)!!/(m-n)!!, 0<=n<=m, else 0, with 0!! := 1. %Y A092081 Diagonals give: A000165 (double factorials of 2*n), A001147(n+1), A002866, A051577-83. %Y A092081 Columns give: A000012 (powers of 1), A000027 (naturals >=2), A005563, 3*A077415, for n=0..3. %K A092081 nonn,easy,tabl %O A092081 0,3 %A A092081 _Wolfdieter Lang_, Mar 19 2004