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 A212671 #3 May 23 2012 14:52:36 %S A212671 1,2,1,2,6,720,362880,6402373705728000, %T A212671 265252859812191058636308480000000, %U A212671 710998587804863451854045647463724949736497978881168458687447040000000000000 %N A212671 A001037(n)!. %Y A212671 Cf. A001037. %K A212671 nonn %O A212671 0,2 %A A212671 _N. J. A. Sloane_, May 23 2012