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 A235610 #12 Nov 30 2016 22:28:17 %S A235610 2,3,5,4,18,13,5,58,116,35,6,179,869,741,96,7,537,6000,12031,4688,267, %T A235610 8,1571,38310,161029,158911,29737,750,9,4587,235781,1706255,3945711, %U A235610 2087325,189648,2118 %N A235610 Array read by antidiagonals: T(n,k) = number of possible positions in standard Connect Four play on a board of height n and width k (n>=1, k>=1). %H A235610 John Tromp, <a href="http://tromp.github.io/c4/c4.html">John's Connect Four Playground</a>, viewed Jan 23 2014. %e A235610 The array as given on the Tromp web site: %e A235610 height %e A235610 ------ %e A235610 8: 9 13343 8424616 1104642469 %e A235610 7: 8 4587 1417322 135385909 14171315454 %e A235610 6: 7 1571 235781 15835683 1044334437 69173028785 4531985219092 %e A235610 5: 6 537 38310 1706255 69763700 2818972642 112829665923 %e A235610 4: 5 179 6000 161029 3945711 94910577 2265792710 54233186631 %e A235610 3: 4 58 869 12031 158911 2087325 27441956 362940958 %e A235610 2: 3 18 116 741 4688 29737 189648 1216721 %e A235610 1: 2 5 13 35 96 267 750 2118 %e A235610 ------------------------------------------------------------------------------- %e A235610 -: 1 2 3 4 5 6 7 <- width %Y A235610 Cf. A212693, A090224, A013582, A235611, A235612. %K A235610 nonn,tabl %O A235610 1,1 %A A235610 _N. J. A. Sloane_, Jan 23 2014