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 A259333 #28 Oct 23 2017 18:30:24 %S A259333 1,1,1,1,4,1,1,9,9,1,1,16,37,16,1,1,25,105,106,25,1,1,36,240,446,245, %T A259333 36,1 %N A259333 Triangle read by rows: T(n,k) = number of column-convex polyominoes with bond-perimeter 2*n+2 and k columns (1 <= k <= n). %H A259333 M.-P. Delest, <a href="/A006026/a006026.pdf">Utilisation des Langages Algébriques et du Calcul Formel Pour le Codage et l'Enumeration des Polyominos</a>, Ph.D. Dissertation, Université Bordeaux I, May 1987. [Scanned copy, with permission. A very large file.] See Figure 9. %H A259333 M.-P. Delest, <a href="/A006026/a006026_1.pdf">Utilisation des Langages Algébriques et du Calcul Formel Pour le Codage et l'Enumeration des Polyominos</a>, Ph.D. Dissertation, Université Bordeaux I, May 1987. (Annotated scanned copy of a small part of the thesis) %H A259333 M.-P. Delest, <a href="http://dx.doi.org/10.1016/0097-3165(88)90071-4">Generating functions for column-convex polyominoes</a>, J. Combin. Theory Ser. A 48 (1988), no. 1, 12-31. %H A259333 S. Dulucq, <a href="/A005819/a005819.pdf">Etude combinatoire de problèmes d'énumeration, d'algorithmique sur les arbres et de codage par des mots</a>, a thesis presented to l'Université de Bordeaux I, 1987. (Annotated scanned copy) %F A259333 There is an explicit formula for T(n,k) - see Delest (1987), Theorem 24. %e A259333 Triangle begins: %e A259333 1, %e A259333 1,1, %e A259333 1,4,1, %e A259333 1,9,9,1, %e A259333 1,16,37,16,1, %e A259333 1,25,105,106,25,1, %e A259333 1,36,240,446,245,36,1, %e A259333 ... %Y A259333 Row sums are A006027. %K A259333 nonn,tabl,more %O A259333 1,5 %A A259333 _N. J. A. Sloane_, Jun 24 2015