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 A213762 #11 Jul 11 2012 18:37:00 %S A213762 1,5,3,15,11,5,37,29,17,7,83,67,43,23,9,177,145,97,57,29,11,367,303, %T A213762 207,127,71,35,13,749,621,429,269,157,85,41,15,1515,1259,875,555,331, %U A213762 187,99,47,17,3049,2537,1769,1129,681,393,217,113,53,19,6119 %N A213762 Rectangular array: (row n) = b**c, where b(h) = 2^(h-1), c(h) = 2*n-3+2*h, n>=1, h>=1, and ** = convolution. %C A213762 Principal diagonal: A213763. %C A213762 Antidiagonal sums: A213764. %C A213762 Row 1, (1,2,4,8,16,...)**(1,3,5,7,9,...): A050488. %C A213762 Row 2, (1,2,4,8,16,...)**(3,5,7,9,11,...). %C A213762 Row 3, (1,2,4,8,16,...)**(5,7,9,11,13,...). %C A213762 For a guide to related arrays, see A213500. %H A213762 Clark Kimberling, <a href="/A213762/b213762.txt">Antidiagonals n = 1..80, flattened</a> %F A213762 T(n,k) = 4*T(n,k-1)-5*T(n,k-2)+2*T(n,k-3). %F A213762 G.f. for row n: f(x)/g(x), where f(x) = x*(2*n - 1 - (2*n - 3)*x) and g(x) = (1 - 2*x)(1 - x )^2. %e A213762 Northwest corner (the array is read by falling antidiagonals): %e A213762 1....5....15...37....83....177 %e A213762 3....11...29...67....145...303 %e A213762 5....17...43...97....207...429 %e A213762 7....23...57...127...269...555 %e A213762 9....29...71...157...331...681 %e A213762 11...35...85...187...393...807 %t A213762 b[n_] := 2^(n - 1); c[n_] := 2 n - 1; %t A213762 t[n_, k_] := Sum[b[k - i] c[n + i], {i, 0, k - 1}] %t A213762 TableForm[Table[t[n, k], {n, 1, 10}, {k, 1, 10}]] %t A213762 Flatten[Table[t[n - k + 1, k], {n, 12}, {k, n, 1, -1}]] %t A213762 r[n_] := Table[t[n, k], {k, 1, 60}] (* A213762 *) %t A213762 Table[t[n, n], {n, 1, 40}] (* A213763 *) %t A213762 s[n_] := Sum[t[i, n + 1 - i], {i, 1, n}] %t A213762 Table[s[n], {n, 1, 50}] (* A213764 *) %Y A213762 Cf. A213500, A213756. %K A213762 nonn,tabl,easy %O A213762 1,2 %A A213762 _Clark Kimberling_, Jun 20 2012