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.

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A114252 a(n) = C(4+2*n,4+n)*C(9+2*n,0+n).

Original entry on oeis.org

1, 66, 2184, 54600, 1178100, 23279256, 434546112, 7801876368, 136246002750, 2331320491500, 39283977292560, 654191853260400, 10794165578796600, 176805993477330000, 2879098129810080000, 46660583690455363200, 753276797952788769660, 12121801610494996922040
Offset: 0

Views

Author

Zerinvary Lajos, Feb 04 2006

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Binomial[4+2n,4+n]Binomial[9+2n,n],{n,0,20}] (* Harvey P. Dale, Aug 30 2015 *)

Formula

From Amiram Eldar, Sep 06 2025: (Start)
a(n) = A002694(n+2) * A030054(n+4).
a(n) ~ 2^(4*n+13) / (Pi*n). (End)

Extensions

More terms from Harvey P. Dale, Aug 30 2015

A348539 Triangle T(n, m) = binomial(n+2, m)*binomial(n+2, n-m), read by rows.

Original entry on oeis.org

1, 3, 3, 6, 16, 6, 10, 50, 50, 10, 15, 120, 225, 120, 15, 21, 245, 735, 735, 245, 21, 28, 448, 1960, 3136, 1960, 448, 28, 36, 756, 4536, 10584, 10584, 4536, 756, 36, 45, 1200, 9450, 30240, 44100, 30240, 9450, 1200, 45, 55, 1815, 18150, 76230, 152460, 152460, 76230, 18150, 1815, 55
Offset: 0

Views

Author

Vladimir Kruchinin, Oct 21 2021

Keywords

Examples

			Triangle starts:
  [0]  1;
  [1]  3,   3;
  [2]  6,  16,    6;
  [3] 10,  50,   50,   10;
  [4] 15, 120,  225,  120,   15;
  [5] 21, 245,  735,  735,  245,  21;
  [6] 28, 448, 1960, 3136, 1960, 448, 28.
  ...
Taylor series: 1 + 3*x*(y + 1) + 2*x^2*(3*y^2 + 8*y + 3) + 10*x^3*(y^3 + 5*y^2 + 5*y + 1) + 15*x^4 (y^4 + 8*y^3 + 15*y^2 + 8*y + 1) + O(x^5)
		

Crossrefs

Cf. A001263, A000217, A002694 (with offset 0 are row sums).

Programs

  • Maple
    T := (n, k) -> binomial(n+2, k) * binomial(n+2, n-k):
    for n from 0 to 9 do seq(T(n, k), k = 0..n) od; # Peter Luschny, Oct 22 2021
  • Mathematica
    T[n_, m_] := Binomial[n + 2, m] * Binomial[n + 2, n - m]; Table[T[n, m], {n, 0, 9}, {m, 0, n}] // Flatten (* Amiram Eldar, Oct 22 2021 *)
  • Maxima
    T(n,m):=binomial(n+2,m)*binomial(n+2,n-m);

Formula

G.f.: (x^2*y^2 - 2*x*y + x^2 - 2*x + 1)/(2*x^4*y^2*sqrt(x^2*y^2 + (-2*x^2-2*x)*y + x^2 - 2*x + 1)) + (x*y + x - 1)/(2*x^4*y^2).
G.f.: diff(N(x,y),x)*N(x,y)/(x*y^2), where N(x,y) is the g.f. of the Narayana numbers A001263.
Previous Showing 41-42 of 42 results.