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 A064191 #13 Jan 26 2020 17:55:27
%S A064191 1,1,1,2,1,1,4,2,2,1,9,4,5,2,1,21,9,12,5,3,1,51,21,30,12,9,3,1,127,51,
%T A064191 76,30,25,9,4,1,323,127,196,76,69,25,14,4,1,835,323,512,196,189,69,44,
%U A064191 14,5,1,2188,835,1353,512,518,189,133,44,20,5,1,5798,2188,3610,1353
%N A064191 Triangle T(n,k) (n >= 0, 0 <= k <= n) generalizing Motzkin numbers.
%C A064191 This triangle appears on page 9 of the linked reference and is defined by Corollary 2.4.
%C A064191 A number triangle with repeated columns of A064189. Production matrix is A070909 (without first term). - _Philippe Deléham_, Dec 02 2009
%H A064191 J. L. Arregui, <a href="http://arXiv.org/abs/math.NT/0109108">Tangent and Bernoulli numbers</a> related to Motzkin and Catalan numbers by means of numerical triangles.
%F A064191 T(n, 0) = Sum_{k=0..n-1} T(n-1, k). For k even, 0 < k <= n, T(n, k) = Sum_{j=k-1..n-1} T(n-1, j). For k odd, 0 < k <= n, T(n, k) = T(n-1, k-1). - _David Wasserman_, Jul 15 2002
%e A064191 Triangle begins
%e A064191 1;
%e A064191 1, 1;
%e A064191 2, 1, 1;
%e A064191 4, 2, 2, 1; ...
%Y A064191 First column gives A001006.
%K A064191 nonn,tabl,easy
%O A064191 0,4
%A A064191 _N. J. A. Sloane_, Sep 21 2001
%E A064191 More terms from _David Wasserman_, Jul 15 2002