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 A225990 #7 Sep 06 2013 02:04:56 %S A225990 60,48720,41801760,36951200000,33792065269760,31520952625612800, %T A225990 29804588641610956800,28466071692659367936000, %U A225990 27397648707462915867279360,26530254119576872937974661120,25817362047962660055225414451200 %N A225990 Number of pairs of orthogonal (-2,3) vectors of length 5*n. %C A225990 Row 4 of A225987. %H A225990 R. H. Hardin, <a href="/A225990/b225990.txt">Table of n, a(n) for n = 1..115</a> %e A225990 Some solutions for n=1 %e A225990 .-2..3...-2..3...-2..3....3..3...-2.-2...-2..3...-2.-2...-2.-2...-2..3...-2..3 %e A225990 .-2..3....3.-2....3..3...-2..3...-2..3...-2..3...-2..3...-2..3....3.-2....3.-2 %e A225990 ..3..3....3..3...-2..3...-2..3...-2.-2...-2..3...-2.-2...-2.-2....3..3...-2..3 %e A225990 .-2..3....3..3....3..3....3..3...-2..3....3..3...-2.-2....3.-2....3..3....3..3 %e A225990 ..3..3....3.-2...-2..3....3.-2...-2.-2....3..3....3.-2...-2.-2...-2..3....3..3 %K A225990 nonn %O A225990 1,1 %A A225990 _R. H. Hardin_, May 22 2013