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.

A244139 Triangle read by rows: terms T(n,k) of a binomial decomposition of n*(n-1) as Sum(k=0..n)T(n,k).

Original entry on oeis.org

0, 0, 0, 0, 0, 2, 0, 0, 12, -6, 0, 0, 48, -72, 36, 0, 0, 160, -540, 720, -320, 0, 0, 480, -3240, 8640, -9600, 3750, 0, 0, 1344, -17010, 80640, -168000, 157500, -54432, 0, 0, 3584, -81648, 645120, -2240000, 3780000, -3048192, 941192, 0, 0, 9216, -367416, 4644864, -25200000, 68040000, -96018048, 67765824, -18874368
Offset: 0

Views

Author

Stanislav Sykora, Jun 22 2014

Keywords

Comments

T(n,k)=k*(1-k)^(k-2)*k^(n-k)*binomial(n,k) for k>1, while T(n,0)=T(n,1)=0 by convention.

Examples

			First rows of the triangle, all summing up to n*(n-1):
0,
0, 0,
0, 0, 2,
0, 0, 12, -6,
0, 0, 48, -72, 36,
0, 0, 160, -540, 720, -320,
0, 0, 480, -3240, 8640, -9600, 3750,
		

Crossrefs

Programs

  • PARI
    seq(nmax)={my(v, n, k, irow);
    v = vector((nmax+1)*(nmax+2)/2); v[1]=0;
    for(n=1, nmax, irow=1+n*(n+1)/2; v[irow]=0; v[irow+1]=0;
      for(k=2, n, v[irow+k]=k*(1-k)^(k-2)*k^(n-k)*binomial(n,k); ); );
    return(v); }
    a=seq(100);