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 A238763 #10 Mar 15 2014 15:24:57 %S A238763 1,0,1,1,0,2,0,2,0,4,1,0,5,0,9,0,3,0,12,0,21,1,0,9,0,30,0,51,0,4,0,25, %T A238763 0,76,0,127,1,0,14,0,69,0,196,0,323,0,5,0,44,0,189,0,512,0,835,1,0,20, %U A238763 0,133,0,518,0,1353,0,2188,0,6,0,70,0,392,0,1422,0 %N A238763 A Motzkin triangle read by rows, 0<=k<=n. %C A238763 Similar to A020474 but with a different enumeration. %C A238763 Compare with the definition of the generalized ballot numbers A238762. %F A238763 Definition: T(0, 0) = 1; T(p, q) = 0 if p < 0 or p > q; T(p, q) = T(p-2, q) + T(p-1, q-1) + T(p, q-2). (The notation is in the style of Knuth, TAOCP 4a (7.2.1.6)). %F A238763 T(n, n) = A001006(n). %F A238763 Sum_{0<=k<=n} T(n, k) = A005043(n+2). %e A238763 [n\k 0 1 2 3 4 5 6 7] %e A238763 [0] 1, %e A238763 [1] 0, 1, %e A238763 [2] 1, 0, 2, %e A238763 [3] 0, 2, 0, 4, %e A238763 [4] 1, 0, 5, 0, 9, %e A238763 [5] 0, 3, 0, 12, 0, 21, %e A238763 [6] 1, 0, 9, 0, 30, 0, 51, %e A238763 [7] 0, 4, 0, 25, 0, 76, 0, 127. %o A238763 (Sage) %o A238763 @CachedFunction %o A238763 def T(p, q): %o A238763 if p == 0 and q == 0: return 1 %o A238763 if p < 0 or p > q: return 0 %o A238763 return T(p-2, q) + T(p-1, q-1) + T(p, q-2) %o A238763 [[T(p, q) for p in (0..q)] for q in (0..9)] %Y A238763 Cf. A001006, A005043, A064189, A020474, A238762. %K A238763 nonn,tabl %O A238763 0,6 %A A238763 _Peter Luschny_, Mar 05 2014