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 A226920 #7 Dec 07 2016 23:29:51 %S A226920 1,1,0,1,0,1,1,0,1,1,1,0,1,1,1,1,0,1,2,2,1,1,0,1,2,4,2,2,1,0,1,2,4,6, %T A226920 5,1,1,0,1,2,5,8,13,4,2,1,0,1,2,5,10,20,19,8,2,1,0,1,2,5,10,28,36,36, %U A226920 9,2 %N A226920 Array read by antidiagonals: T(n,k) = number of completely symmetric polynomials of degree k up to momentum conservation for n particles (n >= 4, k >= 0). %H A226920 R. H. Boels, <a href="http://arxiv.org/abs/1304.7918">On the field theory expansion of superstring five point amplitudes</a>, arXiv preprint arXiv:1304.7918, 2013 %e A226920 Array begins: %e A226920 1,0,1,1,1,1,2,1,2,2,2,2,3,2,3,... %e A226920 1,0,1,1,2,2,5,4,8,9,13,15,23,24,34,... %e A226920 1,0,1,2,4,6,13,19,36,58,97,149,244,364,558,... %e A226920 1,0,1,2,4,8,20,36,83,169,344,680,1342,2518,4695,... %e A226920 1,0,1,2,5,10,28,59,152,364,885,2093,4930,11199,25021,... %e A226920 1,0,1,2,5,10,31,72,205,557,1565,4321,11942,32131,84927,... %e A226920 1,0,1,2,5,11,33,81,246,722,2222,6875,21497,66299,202179,... %e A226920 ... %Y A226920 Columns converge to A226919. %K A226920 nonn,tabl,more %O A226920 4,19 %A A226920 _N. J. A. Sloane_, Jul 12 2013