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 A225988 #7 Sep 06 2013 02:04:51 %S A225988 9,390,20160,1106424,62606544,3611217792,211096262400,12461757863808, %T A225988 741242882016000,44355068641175040,2667095701669969920, %U A225988 161021441731743129600,9754428938330096713728,592621128107578217201664 %N A225988 Number of pairs of orthogonal (-1,2) vectors of length 3*n. %C A225988 Row 2 of A225987. %H A225988 R. H. Hardin, <a href="/A225988/b225988.txt">Table of n, a(n) for n = 1..202</a> %e A225988 All solutions for n=1 %e A225988 .-1.-1...-1..2...-1..2...-1..2....2..2...-1..2...-1.-1....2..2...-1..2 %e A225988 .-1..2...-1.-1....2.-1....2..2...-1..2....2..2...-1.-1...-1..2...-1..2 %e A225988 .-1.-1...-1.-1....2..2....2.-1....2.-1...-1..2...-1..2...-1..2....2..2 %K A225988 nonn %O A225988 1,1 %A A225988 _R. H. Hardin_, May 22 2013