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.

A119789 T(n, k) = floor(log_{goldenratio}(Fibonacci(n)*Fibonacci(k))), with T(n, k) = 0 for n < 3, T(n, 0) = n-2 for n > 2, triangle read by rows.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 1, 1, 1, 2, 2, 2, 2, 3, 4, 3, 3, 3, 4, 5, 6, 4, 4, 4, 5, 6, 7, 8, 5, 5, 5, 6, 7, 8, 9, 10, 6, 6, 6, 7, 8, 9, 10, 11, 12, 7, 7, 7, 8, 9, 10, 11, 12, 13, 14, 8, 8, 8, 9, 10, 11, 12, 13, 14, 15, 16
Offset: 0

Views

Author

Roger L. Bagula, Jul 30 2006

Keywords

Examples

			Triangle begins as:
  0;
  0, 0;
  0, 0, 0;
  1, 1, 1, 2;
  2, 2, 2, 3, 4;
  3, 3, 3, 4, 5, 6;
  4, 4, 4, 5, 6, 7, 8;
  5, 5, 5, 6, 7, 8, 9, 10;
		

Crossrefs

Programs

  • Magma
    A119789:= func< n,k | n le 2 select 0 else k le 1 select n-2 else n+k-4 >;
    [A119789(n,k): k in [0..n], n in [0..12]]; // G. C. Greubel, Dec 17 2022
    
  • Mathematica
    f[n_, k_]= If[n<3, 0, If[k==0, n-2, Floor[Log[GoldenRatio, Fibonacci[n]*Fibonacci[k]]]]];
    Table[f[n, k], {n,0,12}, {k,0,n}]//Flatten
    (* Second program *)
    T[n_, k_]:= T[n, k]= If[n<3, 0, If[k<2, n-2, n+k-4]];
    Table[T[n, k], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Dec 17 2022 *)
  • SageMath
    def A119789(n,k):
        if (n<3): return 0
        elif (k<2): return n-2
        else: return n+k-4
    flatten([[A119789(n,k) for k in range(n+1)] for n in range(13)]) # G. C. Greubel, Dec 17 2022

Formula

T(n, k) = floor(log_{goldenratio}(Fibonacci(n)*Fibonacci(k))), with T(n, k) = 0 for n < 3, T(n, 0) = n-2 for n > 2.
From G. C. Greubel, Dec 17 2022: (Start)
T(n, k) = n+k-4, with T(n, k) = 0 for n < 3, T(n, 0) = n-2 for n >= 3.
T(n, n) = 2*T(n, 0).
T(2*n, n) = 0*[n<2] + A016789(n-2)*[n>1].
T(2*n, n+1) = 3*A001477(n-1), for n > 0.
T(2*n, n-1) = A033627(n) - [n=1].
T(3*n, n) = n*[n<2] + 4*A000027(n-2)*[n>1].
Sum_{k=0..n} T(n, k) = 0*[n<2] + A140090(n-2)*[n>1].
Sum_{k=0..n} (-1)^k * T(n, k) = 0*[n<2] + (-1)^n*A064455(n-2)*[n>1]. (End)

Extensions

Edited by G. C. Greubel, Dec 17 2022