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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A104031 Column 1 of triangle A104030, which is the matrix inverse of the triangle of pairwise sums of trinomial coefficients.

Original entry on oeis.org

1, -5, 32, -299, 4015, -74080, 1801537, -55855829, 2150565968, -100668835739, 5630336915071, -370807060847872, 28403381397111649, -2503741873703550533, 251652633457563092096, -28608467296650576313259, 3652291148549164761101551, -520296573821474451201241696
Offset: 0

Views

Author

Paul D. Hanna, Feb 26 2005

Keywords

Comments

Column 0 of triangle A104030 forms signed Hammersley's polynomial p_n(1) (A006846), offset 1.

Crossrefs

Cf. A104030.

Programs

  • PARI
    {a(n)=if(n<0,0,((matrix(n+2,n+2,m,j,if(m>=j, polcoeff((1+x+x^2)^(m-1)+O(x^(2*j)),2*j-2)+ polcoeff((1+x+x^2)^(m-1)+O(x^(2*j)),2*j-1))))^-1)[n+2,2])}

A259908 Triangle read by rows: Hammersley's numbers c_{j,k} arising from a formula for A085707(n,k).

Original entry on oeis.org

1, 3, 5, 17, 70, 61, 155, 1143, 2317, 1385, 2073, 23716, 82286, 110556, 50521, 38227, 623753, 3243270, 7258090, 7293671, 2702765, 929569, 20454498, 147624355, 484343420, 796220487, 639139202, 199360981
Offset: 1

Views

Author

N. J. A. Sloane, Jul 07 2015

Keywords

Examples

			Triangle begins:
       1,
       3,        5,
      17,       70,        61,
     155,     1143,      2317,      1385,
    2073,    23716,     82286,    110556,     50521,
   38227,   623753,   3243270,   7258090,   7293671,   2702765,
  929569, 20454498, 147624355, 484343420, 796220487, 639139202, 199360981,
  ...
		

Crossrefs

Cf. A085707.
Diagonals are A001469, A000364.

Extensions

Missing row 5 added by Michel Marcus, Feb 07 2023
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