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.

A125172 Triangle T(n,k) with partial column sums of the even-indexed Fibonacci numbers.

Original entry on oeis.org

1, 3, 1, 8, 4, 1, 21, 12, 5, 1, 55, 33, 17, 6, 1, 144, 88, 50, 23, 7, 1, 377, 232, 138, 73, 30, 8, 1, 987, 609, 370, 211, 103, 38, 9, 1, 2584, 1596, 979, 581, 314, 141, 47, 10, 1
Offset: 1

Views

Author

Gary W. Adamson, Nov 22 2006

Keywords

Comments

"Partial column sums" means the 1st column consists of the even-indexed Fibonacci numbers, the 2nd column shows the partial sums of the first column, the 3rd column the partial sums of the 2nd, etc. - R. J. Mathar, Sep 06 2011
Mirror of the fission triangle A193667, as in the Mathematica program below. - Clark Kimberling, Aug 11 2011

Examples

			First few rows of the triangle:
    1;
    3,  1;
    8,  4,  1;
   21, 12,  5,  1;
   55, 33, 17,  6,  1;
  144, 88, 50, 23,  7,  1;
  ...
		

Crossrefs

Cf. A105693 (row sums), A125171, A193667.

Programs

  • Mathematica
    z = 11;
    p[n_, x_] := (x + 1)^n;
    q[n_, x_] := Sum[Fibonacci[k + 1]*x^(n - k), {k, 0, n}];
    p1[n_, k_] := Coefficient[p[n, x], x^k];
    p1[n_, 0] := p[n, x] /. x -> 0;
    d[n_, x_] := Sum[p1[n, k]*q[n - 1 - k, x], {k, 0, n - 1}]
    h[n_] := CoefficientList[d[n, x], {x}]
    TableForm[Table[Reverse[h[n]], {n, 0, z}]]
    Flatten[Table[Reverse[h[n]], {n, -1, z}]]  (* A193667 *)
    TableForm[Table[h[n], {n, 0, z}]]
    Flatten[Table[h[n], {n, -1, z}]]  (* this sequence *)
    (* Clark Kimberling, Aug 11 2011 *)

Formula

T(n,1) = A001906(n).
T(n,k) = T(n-1,k-1) + T(n-1,k), k > 1.
From R. J. Mathar, Sep 06 2011: (Start)
T(n,k) = A125171(n,k), i.e., A125171 without column k=0.
Conjecture: T(n,k) = T(n,k-1) - A121460(n+1,k). (End)

A328083 Triangle read by rows: T(n,k) is the number of nondecreasing Dyck paths of semilength n and height k (1<=k<=n).

Original entry on oeis.org

1, 1, 1, 1, 3, 1, 1, 6, 5, 1, 1, 11, 14, 7, 1, 1, 19, 35, 24, 9, 1, 1, 32, 80, 72, 36, 11, 1, 1, 53, 173, 196, 123, 50, 13, 1
Offset: 1

Views

Author

N. J. A. Sloane, Oct 16 2019

Keywords

Examples

			Triangle begins:
1,
1,1,
1,3,1,
1,6,5,1,
1,11,14,7,1,
1,19,35,24,9,1,
1,32,80,72,36,11,1,
1,53,173,196,123,50,13,1,
...
		

Crossrefs

Cf. A121460.
Showing 1-2 of 2 results.