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.

A297899 Triangle read by rows, T(n, k) = binomial(n, k)*hypergeom([k-n, n+1], [k+2], -4), for n >= 0 and 0 <= k <= n.

Original entry on oeis.org

1, 5, 1, 45, 10, 1, 505, 115, 15, 1, 6345, 1460, 210, 20, 1, 85405, 19765, 2990, 330, 25, 1, 1204245, 279710, 43635, 5220, 475, 30, 1, 17558705, 4088615, 651165, 81955, 8275, 645, 35, 1, 262577745, 61254760, 9901860, 1290520, 139350, 12280, 840, 40, 1
Offset: 0

Views

Author

Peter Luschny, Jan 08 2018

Keywords

Examples

			Triangle starts:
[0]       1
[1]       5,      1
[2]      45,     10,     1
[3]     505,    115,    15,    1
[4]    6345,   1460,   210,   20,   1
[5]   85405,  19765,  2990,  330,  25,  1
[6] 1204245, 279710, 43635, 5220, 475, 30, 1
		

Crossrefs

T(n, 0) = A133305(n). Row sums are A297705, alternating row sums are A131765.
Cf. A103209.

Programs

  • Mathematica
    T[n_, k_] := Binomial[n, k] Hypergeometric2F1[k - n, n + 1, k + 2, -4];
    Table[T[n, k], {n, 0, 8}, {k, 0, n}] // Flatten
    T[n_, k_] := Sum[4^(j - k)*(k + 1)*Binomial[n + j - k, 2*j - k]*Binomial[2*j - k, j - k]/(j + 1), {j, k, n}];
    Flatten[Table[T[n, k], {n, 0, 8}, {k, 0, n}]] (* Detlef Meya, Jan 15 2024 *)
  • PARI
    T(n,k) = sum(j = k, n, 4^(j - k)*(k + 1)*binomial(n + j - k, 2*j - k)* binomial(2*j - k, j - k)/(j + 1)) \\ Andrew Howroyd, Jan 15 2024

Formula

T(n, k) = Sum_{j = k..n} 4^(j - k)*(k + 1)*binomial(n + j - k, 2*j - k)* binomial(2*j - k, j - k)/(j + 1). - Detlef Meya, Jan 15 2024