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.

A247493 Triangle read by rows: T(n, k) = C(n, k)*C(2*k, k)/(k+1) - sum(j = 0..k, (-1)^j*(1-j)^n*C(k, j)/k!), 0<=k<=n.

Original entry on oeis.org

0, 0, 0, 0, 1, 1, 0, 2, 6, 4, 0, 3, 11, 22, 13, 0, 4, 20, 45, 75, 41, 0, 5, 29, 110, 190, 261, 131, 0, 6, 42, 154, 560, 826, 938, 428, 0, 7, 55, 322, 749, 2646, 3570, 3452, 1429, 0, 8, 72, 335, 2499, 3885, 12012, 15198, 12897, 4861, 0, 9, 89, 770, 650, 16947, 21693, 53880, 63915, 48655, 16795, 0, 10, 110, 484, 11660, -8338, 97482
Offset: 0

Views

Author

Peter Luschny, Oct 02 2014

Keywords

Comments

First negative value appears at T(11,5). - Indranil Ghosh, Mar 04 2017

Examples

			0;
0, 0;
0, 1, 1;
0, 2, 6, 4;
0, 3, 11, 22, 13;
0, 4, 20, 45, 75, 41;
0, 5, 29, 110, 190, 261, 131;
0, 6, 42, 154, 560, 826, 938, 428;
		

Crossrefs

Programs

  • Maple
    T := proc(n, k) binomial(n,k)*binomial(2*k,k)/(k+1) - add((-1)^j*(1-j)^n /(j!*(k-j)!), j = 0..k) end:
    for n from 0 to 12 do seq(T(n,k), k=0..n) od;
  • Mathematica
    Flatten[Table[(Binomial[n,k] * Binomial[2k,k] / (k+1)) - Sum[(-1)^j*(1-j)^n*Binomial[k,j]/k!,{j,0,k}],{n,0,10},{k,0,n}]] (* Indranil Ghosh, Mar 04 2017 *)
  • PARI
    tabl(nn) = {for (n=0, nn, for (k=0, n, print1((binomial(n,k)*binomial(2*k,k)/(k+1))-sum(j=0, k, (-1)^j*(1-j)^n*binomial(k,j)/k!),", ",);); print(););};
    tabl(10); \\ Indranil Ghosh, Mar 04 2017

Formula

A105794(n, k) = (-1)^(n-k)*(C(n, k)*Catalan(k) - T(n, k)).
A247491(n) = Sum(k=0..n, (-1)^(n-k+1)*T(n, k)).
A001453(n) = T(n, n).
T(n,k) = A098474 (n,k) - A105794 (n,k). - Michel Marcus, Mar 04 2017