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 A112580 #6 Sep 08 2013 02:57:31 %S A112580 1,12,1152,431424,427723200,920031955200,3777894212198400, %T A112580 27039993414897254400,315084437077115278540800, %U A112580 5667616936309704095784960000,150796432741520745587273564160000 %N A112580 Number of 3-D arrays of nonnegative integers with plane sums 2. %D A112580 P. J. Cameron and T. W. Mueller, Decomposable functors and the exponential principle, II, in preparation %H A112580 P. J. Cameron and T. W. Mueller, <a href="http://arxiv.org/abs/0911.3760v2">Decomposable functors and the exponential principle, II</a>, arXiv:0911.3760 [math.CO] %F A112580 a(n) = b(n) + Sum (k/n)*(n choose k)^3*b(k)*a(n-k), where b(n) counts indecomposable arrays (A112578 with first term 1). %e A112580 a(2)=12: eight 0-1 arrays and four with 2s at opposite vertices. %Y A112580 Cf. A001499 (2-D case), A112578, A112579. %K A112580 nonn,easy %O A112580 1,2 %A A112580 _Peter J. Cameron_, Sep 14 2005