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 A093002 #4 Dec 05 2013 19:56:46 %S A093002 1,2,144,2073600,17557585920000,192668014586363904000000, %T A093002 5116462645455544976110780416000000000 %N A093002 Product of factorials of next n numbers. %C A093002 Essentially the same as A074319. [From _R. J. Mathar_, Sep 08 2008] %e A093002 a(1)=2!=2, a(2)=3!*4!=144, a(3)=4!*5!*6!, a(4)=5!*6!*7!*8!. %o A093002 (PARI) a(n)=prod(i=n+1,2*n,i!) %K A093002 nonn %O A093002 1,2 %A A093002 _Amarnath Murthy_, Mar 29 2004 %E A093002 Corrected and extended by Mohammed Bouayoun (bouyao(AT)wanadoo.fr), Mar 29 2004