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 A053996 #5 May 10 2013 12:44:26 %S A053996 1,3,90,30240,123379200,6462306385920,4516376686991769600, %T A053996 43295772825884473845350400,5810971590951606258595918774272000, %U A053996 11092372326294974332542866301794421571584000 %N A053996 Number of bases of n-dimensional vector space over GF(4). %F A053996 a(n)=(4^n - 1)(4^n - 4)...(4^n - 4^(n-1))/n! %Y A053996 Cf. A053291, A053601. %K A053996 easy,nonn %O A053996 0,2 %A A053996 _Vladeta Jovovic_, Apr 05 2000