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 A213777 #13 Jul 10 2019 08:22:26 %S A213777 1,3,2,7,5,3,15,12,8,5,30,25,19,13,8,58,50,40,31,21,13,109,96,80,65, %T A213777 50,34,21,201,180,154,130,105,81,55,34,365,331,289,250,210,170,131,89, %U A213777 55,655,600,532,469,404,340,275,212,144,89,1164,1075,965,863 %N A213777 Rectangular array: (row n) = b**c, where b(h) = F(h), c(h) = F(h+1), F=A000045 (Fibonacci numbers), n>=1, h>=1, and ** = convolution. %C A213777 Principal diagonal: A001870 %C A213777 Antidiagonal sums: A152881 %C A213777 row 1, (1,1,2,3,5,8,...)**(1,2,3,5,8,13,...): A023610(k-1) %C A213777 row 2, (1,1,2,3,5,8,...)**(2,3,5,8,13,21,...): A067331(k-1) %C A213777 row 3, (1,1,2,3,5,8,...)**(3,5,8,13,21,34,...) %C A213777 For a guide to related arrays, see A213500. %H A213777 Clark Kimberling, <a href="/A213777/b213777.txt">Antidiagonals n=1..80, flattened</a> %F A213777 T(n,k) = 2*T(n,k-1) + T(n,k-2) - 2*T(n,k-3) - T(n,k-4). %F A213777 G.f. for row n: f(x)/g(x), where f(x) = F(n-1) + F(n-2)*x and g(x) = (1 - x - x^2)^2. %F A213777 T(n,k) = (k*Lucas(n+k+1) + Lucas(n)*Fibonacci(k))/5. - _Ehren Metcalfe_, Jul 10 2019 %e A213777 Northwest corner (the array is read by falling antidiagonals): %e A213777 1....3....7....15....30....58 %e A213777 2....5....12...25....50....96 %e A213777 3....8....19...40....80....154 %e A213777 5....13...31...65....130...250 %e A213777 8....21...50...105...210...404 %e A213777 13...34...81...170...340...654 %t A213777 b[n_] := Fibonacci[n]; c[n_] := Fibonacci[n + 1]; %t A213777 t[n_, k_] := Sum[b[k - i] c[n + i], {i, 0, k - 1}] %t A213777 TableForm[Table[t[n, k], {n, 1, 10}, {k, 1, 10}]] %t A213777 Flatten[Table[t[n - k + 1, k], {n, 12}, {k, n, 1, -1}]] %t A213777 r[n_] := Table[t[n, k], {k, 1, 60}] (* A213777 *) %t A213777 Table[t[n, n], {n, 1, 40}] (* A001870 *) %t A213777 s[n_] := Sum[t[i, n + 1 - i], {i, 1, n}] %t A213777 Table[s[n], {n, 1, 50}] (* A152881 *) %Y A213777 Cf. A213500. %K A213777 nonn,tabl,easy %O A213777 1,2 %A A213777 _Clark Kimberling_, Jun 21 2012