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 A007871 #12 Aug 13 2015 19:43:58 %S A007871 1,1,3,12,66,420,3200,27144,258705,2704592,30898506,381922380, %T A007871 5090938955 %N A007871 Number of simple juggling patterns of n balls. %C A007871 Simple juggling patterns are cycles in the juggling state graph that pass through the base state <1,1,...,1>. - _Steve Butler_, Aug 13 2015 %D A007871 See also rec.juggling newsgroup. %K A007871 nonn,hard %O A007871 1,3 %A A007871 Jack Boyce (jboyce(AT)physics.berkeley.edu) %E A007871 a(9)-a(13) from _Steve Butler_, Aug 13 2015