cp's OEIS Frontend

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.

A083861 Square array T(n,k) of second binomial transforms of generalized Fibonacci numbers, read by ascending antidiagonals, with n, k >= 0.

This page as a plain text file.
%I A083861 #44 Sep 08 2022 08:45:10
%S A083861 0,0,1,0,1,5,0,1,5,19,0,1,5,20,65,0,1,5,21,75,211,0,1,5,22,85,275,665,
%T A083861 0,1,5,23,95,341,1000,2059,0,1,5,24,105,409,1365,3625,6305,0,1,5,25,
%U A083861 115,479,1760,5461,13125,19171,0,1,5,26,125,551,2185,7573,21845,47500,58025
%N A083861 Square array T(n,k) of second binomial transforms of generalized Fibonacci numbers, read by ascending antidiagonals, with n, k >= 0.
%C A083861 Row n >= 0 of the array gives the solution to the recurrence b(k) = 5*b(k-1) + (n - 6)*b(k-2) for k >= 2 with b(0) = 0 and b(1) = 1. The rows are the binomial transforms of the rows of array A083857. The rows are the second binomial transforms of the generalized Fibonacci numbers in array A083856.
%H A083861 G. C. Greubel, <a href="/A083861/b083861.txt">Antidiagonals n = 0..100, flattened</a>
%H A083861 OEIS, <a href="https://oeis.org/transforms.html">Transformations of integer sequences</a>.
%F A083861 T(n, k) = (((5 + sqrt(4*n + 1))/2)^k - ((5 - sqrt(4*n + 1))/2)^k)/sqrt(4*n + 1).
%F A083861 O.g.f. for row n >= 0: -x/(-1 + 5*x + (n-6)*x^2) . - _R. J. Mathar_, Dec 02 2007
%F A083861 From _Petros Hadjicostas_, Dec 25 2019: (Start)
%F A083861 T(n,k) = 5*T(n,k-1) + (n - 6)*T(n,k-2) for k >= 2 with T(n,0) = 0 and T(n,1) = 1 for all n >= 0.
%F A083861 T(n,k) = Sum_{i = 0..k} binomial(k,i) * A083857(n,i).
%F A083861 T(n,k) = Sum_{i = 0..k} Sum_{j = 0..i} binomial(k,i) * binomial(i,j) * A083856(n,j). (End)
%e A083861 Array T(n,k) (with rows n >= 0 and columns k >= 0) begins as follows:
%e A083861   0, 1, 5, 19,  65, 211,  665,  2059,  6305,  19171, ...
%e A083861   0, 1, 5, 20,  75, 275, 1000,  3625, 13125,  47500, ...
%e A083861   0, 1, 5, 21,  85, 341, 1365,  5461, 21845,  87381, ...
%e A083861   0, 1, 5, 22,  95, 409, 1760,  7573, 32585, 140206, ...
%e A083861   0, 1, 5, 23, 105, 479, 2185,  9967, 45465, 207391, ...
%e A083861   0, 1, 5, 24, 115, 551, 2640, 12649, 60605, 290376, ...
%e A083861   0, 1, 5, 25, 125, 625, 3125, 15625, 78125, 390625, ...
%e A083861   ...
%p A083861 seq(seq(round( (((5+sqrt(4*(n-k)+1))/2)^k - ((5-sqrt(4*(n-k)+1))/2)^k)/sqrt(4*(n-k)+1) ), k=0..n), n=0..10); # _G. C. Greubel_, Dec 27 2019
%t A083861 T[n_, k_]:= Round[(((5 +Sqrt[4*n+1])/2)^k - ((5 -Sqrt[4*n+1])/2)^k)/Sqrt[4*n+1]]; Table[T[n-k, k], {n, 0, 10}, {k, 0, n}]//Flatten (* _G. C. Greubel_, Dec 27 2019 *)
%o A083861 (PARI) T(n, k) = round( (((5+sqrt(4*n+1))/2)^k - ((5-sqrt(4*n+1))/2)^k)/sqrt(4*n + 1) );
%o A083861 for(n=0,10, for(k=0,n, print1(T(n-k,k), ", "))) \\ _G. C. Greubel_, Dec 27 2019
%o A083861 (Magma)
%o A083861 T:= func< n,k | Round( (((5+Sqrt(4*n+1))/2)^k - ((5-Sqrt(4*n+1))/2)^k)/Sqrt(4*n + 1) ) >;
%o A083861 [T(n-k,k): k in [0..n], n in [0..10]]; // _G. C. Greubel_, Dec 27 2019
%o A083861 (Sage) [[round( (((5+sqrt(4*(n-k)+1))/2)^k - ((5-sqrt(4*(n-k)+1))/2)^k)/sqrt(4*(n-k)+1) ) for k in (0..n)] for n in (0..10)] # _G. C. Greubel_, Dec 27 2019
%Y A083861 Rows include A001047 (n=0), A093131 (n=1), A002450 (n=2), A004254 (n=5), A000351 (n=6), A052918 (n=7), A015535 (n=8), A015536 (n=9), A015537 (n=10).
%Y A083861 Cf. A083856 (second inverse binomial transform), A083856 (first inverse binomial transform), A082297 (main diagonal).
%K A083861 easy,nonn,tabl
%O A083861 0,6
%A A083861 _Paul Barry_, May 06 2003
%E A083861 Name and various sections edited by _Petros Hadjicostas_, Dec 25 2019