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 A213765 #18 Jul 10 2019 11:16:53 %S A213765 1,4,1,10,5,2,21,14,9,3,40,31,24,14,5,72,61,52,38,23,8,125,112,101,83, %T A213765 62,37,13,212,197,184,162,135,100,60,21,354,337,322,296,263,218,162, %U A213765 97,34,585,566,549,519,480,425,353,262,157,55,960,939,920,886 %N A213765 Rectangular array: (row n) = b**c, where b(h) = 2*n-1, c(h) = F(n-1+h), F=A000045 (Fibonacci numbers), n>=1, h>=1, and ** = convolution. %C A213765 Principal diagonal: A213766. %C A213765 Antidiagonal sums: A213767. %C A213765 Row 1, (1,3,5,7,9,...)**(1,1,2,3,5,...): A001891. %C A213765 Row 2, (1,3,5,7,9,...)**(1,2,3,5,8,...): A023652. %C A213765 Row 3, (1,3,5,7,9,...)**(2,3,5,8,13,...). %C A213765 For a guide to related arrays, see A213500. %H A213765 Clark Kimberling, <a href="/A213765/b213765.txt">Antidiagonals n = 1..60, flattened</a> %F A213765 T(n,k) = 3*T(n,k-1)-2*T(n,k-2)-T(n,k-3)+T(n,k-4). %F A213765 G.f. for row n: f(x)/g(x), where f(x) = x*(F(n) + F(n+1)*x - F(n-1)*x^2) and g(x) = (1 - x - x^2)(1 - x )^2. %F A213765 T(n,k) = F(n+k+4) - 2*k*F(n+1) - F(n+4), F = A000045. - _Ehren Metcalfe_, Jul 10 2019 %e A213765 Northwest corner (the array is read by falling antidiagonals): %e A213765 1....4....10....21....40....72 %e A213765 1....5....14....31....61....112 %e A213765 2....9....24....52....101...184 %e A213765 3....14...38....83....162...296 %e A213765 5....23...62....135...263...480 %e A213765 8....37...100...218...425...776 %e A213765 13...60...162...353...688...1256 %t A213765 b[n_] := 2 n - 1; c[n_] := Fibonacci[n]; %t A213765 t[n_, k_] := Sum[b[k - i] c[n + i], {i, 0, k - 1}] %t A213765 TableForm[Table[t[n, k], {n, 1, 10}, {k, 1, 10}]] %t A213765 Flatten[Table[t[n - k + 1, k], {n, 12}, {k, n, 1, -1}]] %t A213765 r[n_] := Table[t[n, k], {k, 1, 60}] (* A213765 *) %t A213765 Table[t[n, n], {n, 1, 40}] (* A213766 *) %t A213765 s[n_] := Sum[t[i, n + 1 - i], {i, 1, n}] %t A213765 Table[s[n], {n, 1, 50}] (* A213767 *) %Y A213765 Cf. A213500. %K A213765 nonn,tabl,easy %O A213765 1,2 %A A213765 _Clark Kimberling_, Jun 21 2012