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 A213768 #16 Jul 10 2019 10:47:09 %S A213768 1,4,3,10,8,5,21,18,12,7,40,35,26,16,9,72,64,49,34,20,11,125,112,88, %T A213768 63,42,24,13,212,191,152,112,77,50,28,15,354,320,257,192,136,91,58,32, %U A213768 17,585,530,428,323,232,160,105,66,36,19 %N A213768 Rectangular array: (row n) = b**c, where b(h) = F(h), c(h) = 2*n-3+2*h, F=A000045 (Fibonacci numbers), n>=1, h>=1, and ** = convolution. %C A213768 Principal diagonal: A213769. %C A213768 Antidiagonal sums: A213770. %C A213768 Row 1, (1,1,2,3,5,...)**(1,3,5,7,9,...): A001891. %C A213768 Row 2, (1,1,2,3,5,...)**(3,5,7,9,11,...). %C A213768 Row 3, (1,1,2,3,5,...)**(5,7,9,11,13,...). %C A213768 For a guide to related arrays, see A213500. %H A213768 Clark Kimberling, <a href="/A213768/b213768.txt">Antidiagonals n=1..80, flattened</a> %F A213768 T(n,k) = 3*T(n,k-1)-2*T(n,k-2)-T(n,k-3)+T(n,k-4). %F A213768 G.f. for row n: f(x)/g(x), where f(x) = x*(2*n - 1 - (2*n - 3)*x) and g(x) = (1 - x - x^2)(1 - x )^2. %F A213768 T(n,k) = 2*n*Fibonacci(k+2) + Lucas(k+2) - 2*(k+n) - 3. - _Ehren Metcalfe_, Jul 08 2019 %e A213768 Northwest corner (the array is read by falling antidiagonals): %e A213768 1....4....10...21...40....72....125 %e A213768 3....8....18...35...64....112...191 %e A213768 5....12...26...49...88....152...257 %e A213768 7....16...34...63...112...192...323 %e A213768 9....20...42...77...136...232...389 %e A213768 11...24...50...91...160...272...455 %t A213768 b[n_] := Fibonacci[n]; c[n_] := 2 n - 1; %t A213768 t[n_, k_] := Sum[b[k - i] c[n + i], {i, 0, k - 1}] %t A213768 TableForm[Table[t[n, k], {n, 1, 10}, {k, 1, 10}]] %t A213768 Flatten[Table[t[n - k + 1, k], {n, 12}, {k, n, 1, -1}]] %t A213768 r[n_] := Table[t[n, k], {k, 1, 60}] (* A213768 *) %t A213768 Table[t[n, n], {n, 1, 40}] (* A213769 *) %t A213768 s[n_] := Sum[t[i, n + 1 - i], {i, 1, n}] %t A213768 Table[s[n], {n, 1, 50}] (* A213770 *) %Y A213768 Cf. A001891, A213500, A213769, A213770. %K A213768 nonn,tabl,easy %O A213768 1,2 %A A213768 _Clark Kimberling_, Jun 21 2012