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 A258709 #10 Jul 25 2015 20:45:31 %S A258709 1,1,1,2,1,1,4,2,1,1,9,4,2,1,1,21,8,4,2,1,1,51,17,8,4,2,1,1,127,37,16, %T A258709 8,4,2,1,1,323,82,33,16,8,4,2,1,1,835,185,69,32,16,8,4,2,1,1,2188,423, %U A258709 146,65,32,16,8,4,2,1,1,5798,978,312,133,64,32,16,8,4,2,1,1 %N A258709 Triangle of generalized Catalan numbers read by rows. %H A258709 Manfred Scheucher, <a href="/A258709/b258709.txt">Table of n, a(n) for n = 0..5150</a> %H A258709 P. R. Stein and M. S. Waterman, <a href="http://dx.doi.org/10.1016/0012-365X(79)90033-5">On some new sequences generalizing the Catalan and Motzkin numbers</a>, Discrete Math., 26 (1978), 261-272. %H A258709 P. R. Stein and M. S. Waterman, <a href="/A001006/a001006_4.pdf">On some new sequences generalizing the Catalan and Motzkin numbers</a> [Corrected annotated scanned copy] See Table 1. %H A258709 Manfred Scheucher, <a href="/A258709/a258709.sage.txt">Sage Script</a> %e A258709 Triangle begins %e A258709 1, %e A258709 1,1, %e A258709 2,1,1, %e A258709 4,2,1,1, %e A258709 9,4,2,1,1, %e A258709 21,8,4,2,1,1, %e A258709 51,17,8,4,2,11, %e A258709 127,37,16,8,4,2,1,1, %e A258709 323,82,33,16,8,4,2,1,1, %e A258709 835,185,69,32,16,8,4,2,1,1, %e A258709 ... %Y A258709 Cf. A064645. %Y A258709 First 3 columns are A001006, A004148, A004149. %K A258709 nonn,tabl,easy %O A258709 0,4 %A A258709 _N. J. A. Sloane_, Jun 13 2015 %E A258709 Corrected and extended by _Manfred Scheucher_, Jul 25 2015