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 A047660 #13 Jun 24 2017 13:53:20 %S A047660 1,1,0,1,2,40,0,703760,131328,300241541128192,0, %T A047660 28170013344558609991874248704,24595658799308603392, %U A047660 9502080486519653717758562294813775233459455787008,0 %N A047660 Number of self-complementary 2-plexes. %H A047660 E. M. Palmer, <a href="http://dx.doi.org/10.1016/0012-365X(73)90069-1">On the number of n-plexes</a>, Discrete Math., 6 (1973), 377-390. %Y A047660 Cf. A000171, A051251. %K A047660 nonn,nice %O A047660 1,5 %A A047660 _N. J. A. Sloane_ %E A047660 More terms from _Vladeta Jovovic_