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.

A338523 Triangle T(n,m) = (2*m*n+2*n-2*m^2+1)*C(2*n+2,2*m+1)/(4*n+2).

Original entry on oeis.org

1, 2, 2, 3, 14, 3, 4, 44, 44, 4, 5, 100, 238, 100, 5, 6, 190, 828, 828, 190, 6, 7, 322, 2233, 4092, 2233, 322, 7, 8, 504, 5096, 14872, 14872, 5096, 504, 8, 9, 744, 10332, 43992, 70070, 43992, 10332, 744, 9, 10, 1050, 19176, 112200, 260780, 260780, 112200, 19176, 1050, 10
Offset: 0

Views

Author

Vladimir Kruchinin, Nov 01 2020

Keywords

Examples

			1,
2, 2,
3, 14, 3,
4, 44, 44, 4,
5, 100, 238, 100, 5,
6, 190, 828, 828, 190, 6,
7, 322, 2233, 4092, 2233, 322, 7
		

Crossrefs

2nd column=2*A002412.

Programs

  • Mathematica
    Table[Sum[Binomial[n + 1, 2 k + 1] Binomial[n - 2 k, m - k] (k + 1)*4^k, {k, 0, n} ], {n, 0, 9}, {m, 0, n}] // Flatten (* Michael De Vlieger, Nov 04 2020 *)
  • Maxima
    T(n,m):=((2*m*n+2*n-2*m^2+1)*binomial(2*n+2,2*m+1))/(4*n+2);

Formula

G.f.: (1/(1-x-x*y-4*x^2*y/(1-x-x*y)))^2.
T(n,m) = Sum_{k=0..n} C(n+1,2*k+1)*C(n-2*k,m-k)*(k+1)*4^k.
A045563(n) = (Sum_{m=0..n} T(n,m))/2^n.