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.

Previous Showing 11-16 of 16 results.

A143211 Triangle read by rows, T(n,k) = Fibonacci(n)*Fibonacci(k).

Original entry on oeis.org

1, 1, 1, 2, 2, 4, 3, 3, 6, 9, 5, 5, 10, 15, 25, 8, 8, 16, 24, 40, 64, 13, 13, 26, 39, 65, 104, 169, 21, 21, 42, 63, 105, 168, 273, 441, 34, 34, 68, 102, 170, 272, 442, 714, 1156, 55, 55, 110, 165, 275, 440, 715, 1155, 1870, 3025, 89, 89, 178, 267, 445, 712, 1157, 1869
Offset: 1

Views

Author

Gary W. Adamson, Jul 30 2008

Keywords

Examples

			First few rows of the triangle:
   1;
   1,  1;
   2,  2,  4;
   3,  3,  6,  9;
   5,  5, 10, 15,  25;
   8,  8, 16, 24,  40,  64;
  13, 13, 26, 39,  65, 104, 169;
  21, 21, 42, 63, 105, 168, 273, 441;
  ...
		

Crossrefs

Cf. A000045 (left border), A007598 (right border), A127647,
Cf. A024458 (diagonal row sums), A143212 (row sums).

Programs

  • Magma
    F:=Fibonacci; [F(n)*F(k): k in [1..n], n in [1..12]]; // G. C. Greubel, Jul 20 2024
    
  • Mathematica
    With[{F=Fibonacci}, Table[F[k]*F[n], {n,12}, {k,n}]]//Flatten (* G. C. Greubel, Jul 20 2024 *)
  • SageMath
    def A143211(n,k): return fibonacci(n)*fibonacci(k)
    flatten([[A143211(n,k) for k in range(1,n+1)] for n in range(1,13)]) # G. C. Greubel, Jul 20 2024

Formula

T(n, k) = Fibonacci(n)*Fibonacci(k).
T(n, k) = A127647 * A000012 * A127647, as infinite lower triangular matrices.
T(n, 1) = A000045(n).
T(n, n) = A007598(n).
Sum_{k=1..n} T(n, k) = A143212(n).
From G. C. Greubel, Jul 20 2024: (Start)
Sum_{k=1..n} (-1)^(k-1)*T(n, k) = (-1)^(n-1)*Fibonacci(n)*(Fibonacci(n-1) - (-1)^n).
Sum_{k=1..floor((n+1)/2)} T(n-k+1, k) = A024458(n). (End)

A132921 Triangle read by rows: T(n,k) = n + Fibonacci(k) - 1, 1 <= k <= n.

Original entry on oeis.org

1, 2, 2, 3, 3, 4, 4, 4, 5, 6, 5, 5, 6, 7, 9, 6, 6, 7, 8, 10, 13, 7, 7, 8, 9, 11, 14, 19, 8, 8, 9, 10, 12, 15, 20, 28, 9, 9, 10, 11, 13, 16, 21, 29, 42, 10, 10, 11, 12, 14, 17, 22, 30, 43, 64, 11, 11, 12, 13, 15, 18, 23, 31, 44, 65, 99, 12, 12, 13, 14, 16, 19, 24, 32, 45, 66, 100, 155
Offset: 1

Views

Author

Gary W. Adamson, Sep 05 2007

Keywords

Comments

Right border = A081659, row sums = A132922: (1, 4, 10, 19, 32, ...).

Examples

			First few rows of the triangle are:
  1;
  2, 2;
  3, 3, 4;
  4, 4, 5, 6;
  5, 5, 6, 7, 9;
  ...
Column 3 = 4, 5, 6, 7, ...; since A081659(2) = 4.
		

Crossrefs

Row sums are A132922.

Programs

  • Mathematica
    T[n_,k_]:=n+Fibonacci[k]-1;Table[T[n,k],{n,12},{k,n}]//Flatten (* James C. McMahon, Mar 09 2025 *)
  • PARI
    T(n,k)=if(k<=n, n + fibonacci(k) - 1, 0) \\ Andrew Howroyd, Sep 01 2018

Formula

Equals (A127648 * A000012 + A000012 * A127647) - A000012 as infinite lower triangular matrices.

Extensions

Name clarified and terms a(56) and beyond from Andrew Howroyd, Sep 01 2018

A131411 Triangle read by rows: T(n,k) = Fibonacci(n) + Fibonacci(k) - 1.

Original entry on oeis.org

1, 1, 1, 2, 2, 3, 3, 3, 4, 5, 5, 5, 6, 7, 9, 8, 8, 9, 10, 12, 15, 13, 13, 14, 15, 17, 20, 25, 21, 21, 22, 23, 25, 28, 33, 41, 34, 34, 35, 36, 38, 41, 46, 54, 67, 55, 55, 56, 57, 59, 62, 67, 75, 88, 109, 89, 89, 90, 91, 93, 96, 101, 109, 122, 143, 177, 144, 144, 145, 146, 148, 151, 156, 164, 177, 198, 232, 287
Offset: 1

Views

Author

Gary W. Adamson, Jul 08 2007

Keywords

Comments

Left column = Fibonacci numbers. Right column = A001595: (1, 1, 3, 5, 9, 15, 25,...).
Row sums = A131412: (1, 2, 7, 15, 32, 62, 117, 214,...).

Examples

			First few rows of the triangle are:
   1;
   1,  1;
   2,  2,  3;
   3,  3,  4,  5;
   5,  5,  6,  7,  9;
   8,  8,  9, 10, 12, 15;
  13, 13, 14, 15, 17, 20, 25;
  21, 21, 22, 23, 25, 28, 33, 41;
  ...
		

Crossrefs

Programs

  • GAP
    F:=Fibonacci;; Flat(List([1..15], n-> List([1..n], k-> F(n) +F(k) -1 ))); # G. C. Greubel, Jul 13 2019
  • Magma
    F:=Fibonacci; [F(n)+F(k)-1: k in [1..n], n in [1..15]]; // G. C. Greubel, Jul 13 2019
    
  • Mathematica
    With[{F=Fibonacci}, Table[F[n]+F[k]-1, {n,15}, {k,n}]//Flatten] (* G. C. Greubel, Jul 13 2019 *)
  • PARI
    T(n,k) = if(k<=n, fibonacci(n) + fibonacci(k) - 1, 0); \\ Andrew Howroyd, Aug 10 2018
    
  • Sage
    f=fibonacci; [[f(n)+f(k)-1 for k in (1..n)] for n in (1..15)] # G. C. Greubel, Jul 13 2019
    

Formula

Equals A131410 + A104763 - A000012 as infinite lower triangular matrices.

Extensions

Name changed and terms a(56) and beyond from Andrew Howroyd, Aug 10 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

A144154 A Fibonacci triangle, row sums = A023610.

Original entry on oeis.org

1, 2, 1, 3, 2, 2, 5, 3, 4, 5, 8, 5, 6, 6, 5, 13, 8, 10, 9, 10, 8, 21, 13, 16, 15, 15, 16, 13, 34, 21, 26, 24, 25, 24, 26, 21, 55, 34, 42, 39, 40, 40, 39, 42, 34
Offset: 1

Views

Author

Gary W. Adamson, Sep 12 2008

Keywords

Comments

Row sums = A023610: (1, 3, 7, 15, 30, 58,...).

Examples

			First few rows of the triangle =
1;
2, 1;
3, 2, 2;
5, 3, 4, 3;
8, 5, 6, 6, 5;
13, 8, 10, 9, 10, 8;
21, 13, 16, 15, 15, 16, 13;
34, 21, 26, 24, 25, 24, 26, 21;
... Row 4 = (5, 3, 4, 3) = termwise products of (5, 3, 2, 1) and (1, 1, 2, 3).
		

Crossrefs

Formula

The triangle as an infinite lower triangular matrix = A * B. A = a Fibonacci subsequences decrescendo triangle: (1; 2,1; 3,2,1; 5,3,2,1;...) and B = A127647, an infinite lower triangular matrix with the Fibonacci sequence as the main diagonal and the rest zeros.

A152203 Triangle T(n,k) = (2n+1-2k)*fibonacci(k), read by rows.

Original entry on oeis.org

1, 3, 1, 5, 3, 2, 7, 5, 6, 3, 9, 7, 10, 9, 5, 11, 9, 14, 15, 15, 8, 13, 11, 18, 21, 25, 24, 13, 15, 13, 22, 27, 35, 40, 39, 21, 17, 15, 26, 33, 45, 56, 65, 63, 34, 19, 17, 30, 39, 55, 72, 91, 105, 102, 55, 21, 19, 34, 45, 65, 88, 117, 147, 170, 165
Offset: 1

Views

Author

Gary W. Adamson, Nov 29 2008

Keywords

Examples

			First few rows of the triangle =
1;
3, 1;
5, 3, 2;
7, 5, 6, 3;
9, 7, 10, 9, 5;
11, 9, 14, 15, 15, 8;
13, 11, 18, 21, 25, 24, 13;
15, 13, 22, 27, 35, 40, 39, 21;
17, 15, 26, 33, 45, 56, 65, 63, 34;
...
Row 4 = (7, 5, 6, 3) = termwise products of (7, 5, 3, 1) and (1, 1, 2, 3).
		

Crossrefs

Cf. A099375, A127647, A001891 (row sums).

Programs

  • Mathematica
    Flatten[Table[(2n+1-2k)Fibonacci[k],{n,15},{k,n}]] (* Harvey P. Dale, Mar 15 2015 *)

Formula

Triangle read by rows, A099375 * A127647 = termwise products of odd numbers and the Fibonacci series.
Previous Showing 11-16 of 16 results.