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 A216201 #10 Mar 16 2013 10:26:43 %S A216201 1,1,1,1,2,1,1,3,3,0,0,4,6,3,0,0,4,10,9,0,0,0,0,14,19,9,0,0,0,0,14,33, %T A216201 28,0,0,0,0,0,0,47,61,28,0,0,0,0,0,0,47,108,89,0,0,0,0,0,0,0,0,155, %U A216201 197,89,0,0,0,0 %N A216201 Square array T, read by antidiagonals : T(n,k) = 0 if n-k>=3 or if k-n>=4, T(2,0) = T(1,0) = T(0,0) = T(0,1) = T(0,2) = T(0,3) = 1, T(n,k) = T(n-1,k) + T(n,k-1). %D A216201 E. Lucas, Théorie des nombres, Tome 1, Albert Blanchard, Paris, 1958, p.89 %H A216201 E. Lucas, <a href="http://visualiseur.bnf.fr/Visualiseur?Destination=Gallica&O=NUMM-29021">Théorie des nombres</a>, Tome 1, Jacques Gabay, Paris, 1991, p.89 %F A216201 T(n,n) = A052975(n). %F A216201 T(n,n+1) = A060557(n). %F A216201 T(n+1,n) = T(n+2,n) = A094790(n+1). %F A216201 T(n,n+2) = T(n,n+3) = A094789(n+1). %F A216201 Sum_{k, 0<=k<=n} T(n-k,k) = (-1)^n*A078038(n). %e A216201 Square array begins: %e A216201 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, ... row n = 0 %e A216201 1, 2, 3, 4, 4, 0, 0, 0, 0, 0, 0, 0, 0, ... row n = 1 %e A216201 1, 3, 6, 10, 14, 14, 0, 0, 0, 0, 0, 0, 0, ... row n = 2 %e A216201 0, 3, 9, 19, 33, 47, 47, 0, 0, 0, 0, 0, 0, ... row n = 3 %e A216201 0, 0, 9, 28, 61, 108, 155, 155, 0, 0, 0, 0, 0, ... row n = 4 %e A216201 0, 0, 0, 28, 89, 197, 352, 507, 507, 0, 0, 0, 0, ... row n = 5 %e A216201 0, 0, 0, 0, 89, 286, 638,1147,1652,1652, 0, 0, 0, ... row n = 6 %e A216201 ... %Y A216201 Cf. A052975, A060557, A078038, A095789, A094790 %K A216201 nonn,tabl %O A216201 0,5 %A A216201 _Philippe Deléham_, Mar 12 2013