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 A181571 #5 Mar 30 2012 16:51:58 %S A181571 1,6,40,300,2475,22022,208208,2068560,21414900,229523800,2533942752, %T A181571 28698821320,332357673375,3925129083750,47167131780000, %U A181571 575637606165600,7123515376299300,89266155250239000,1131410294476020000,14489559984061890000,187330691180608155180,2443121585638964379864 %N A181571 Third column of triangle in A179898. %Y A181571 Cf. A179898, A005700, A005701. %K A181571 nonn %O A181571 1,2 %A A181571 _N. J. A. Sloane_, Jan 30 2011