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.

Showing 1-2 of 2 results.

A132922 Row sums of triangle A132921.

Original entry on oeis.org

1, 4, 10, 19, 32, 50, 75, 110, 160, 233, 342, 508, 765, 1168, 1806, 2823, 4452, 7070, 11287, 18090, 29076, 46829, 75530, 121944, 197017, 318460, 514930, 832795, 1347080, 2179178, 3525507, 5703878, 9228520, 14931473, 24159006, 39089428, 63247317, 102335560
Offset: 1

Views

Author

Gary W. Adamson, Sep 05 2007

Keywords

Examples

			a(4) = 19 = sum of row 4 terms of triangle A132921: (4 + 4 + 5 + 6).
a(5) = 32 = (1, 4, 6, 4, 1) dot (1, 3, 3, 0, 1) = (1 + 12 + 18 + 0 + 1).
		

Crossrefs

Cf. A132922.

Programs

  • Mathematica
    LinearRecurrence[{4, -5, 1, 2, -1},{1, 4, 10, 19, 32},50] (* or *)
    a[n_]:=n*(n - 1) + Fibonacci[n + 2] - 1; Array[a, 50] (* Stefano Spezia, Sep 01 2018 *)
  • PARI
    a(n) = n*(n-1) + fibonacci(n+2) - 1; \\ Andrew Howroyd, Aug 28 2018
    
  • PARI
    Vec((1 - x^2 - 2*x^3)/((1 - x)^3*(1 - x - x^2)) + O(x^40)) \\ Andrew Howroyd, Aug 28 2018

Formula

Binomial transform of [1, 3, 3, 0, 1, -1, 2, -3, 5, -8, ...].
From Andrew Howroyd, Aug 28 2018: (Start)
a(n) = 4*a(n-1) - 5*a(n-2) + a(n-3) + 2*a(n-4) - a(n-5) for n > 5.
a(n) = n*(n-1) + Fibonacci(n+2) - 1.
G.f.: x*(1 - x^2 - 2*x^3)/((1 - x)^3*(1 - x - x^2)).
(End)

Extensions

Terms a(11) and beyond from Andrew Howroyd, Aug 28 2018

A132919 Triangle read by rows: T(n,k) = Fibonacci(n) + k - 1.

Original entry on oeis.org

1, 1, 2, 2, 3, 4, 3, 4, 5, 6, 5, 6, 7, 8, 9, 8, 9, 10, 11, 12, 13, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 24, 25, 26, 27, 28, 34, 35, 36, 37, 38, 39, 40, 41, 42, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99
Offset: 1

Views

Author

Gary W. Adamson, Sep 05 2007

Keywords

Comments

Left border = Fibonacci numbers, right border = A081659.
Infinite lower triangular matrix by rows: n-th row = n terms of: F(n) followed by (F(n) + 1), (F(n) + 2), (F(n) + 3), ...

Examples

			First few rows of the triangle:
  1;
  1,  2;
  2,  3,  4;
  3,  4,  5,  6;
  5,  6,  7,  8,  9;
  8,  9, 10, 11, 12, 13;
  ...
		

Crossrefs

Row sums are A132920.

Programs

  • Mathematica
    T[n_,k_]:=Fibonacci[n]+k-1;Table[T[n,k],{n,11},{k,n}]//Flatten (* James C. McMahon, Mar 09 2025 *)
  • PARI
    T(n,k) = if(k<=n, fibonacci(n) + k - 1, 0); \\ Andrew Howroyd, Aug 10 2018

Extensions

Name changed and terms a(56) and beyond from Andrew Howroyd, Aug 10 2018
Showing 1-2 of 2 results.