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.

A045912 Triangle of coefficients of characteristic polynomial of negative Pascal matrix with (i,j)-th entry -C(i+j-2,i-1).

Original entry on oeis.org

1, 1, 1, 1, 3, 1, 1, 9, 9, 1, 1, 29, 72, 29, 1, 1, 99, 626, 626, 99, 1, 1, 351, 6084, 13869, 6084, 351, 1, 1, 1275, 64974, 347020, 347020, 64974, 1275, 1, 1, 4707, 744193, 9952274, 21537270, 9952274, 744193, 4707, 1, 1, 17577, 8965323, 321541977, 1545936516, 1545936516, 321541977, 8965323, 17577, 1
Offset: 0

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Author

Fred Lunnon, Dec 11 1999

Keywords

Examples

			1;
1,1;
1,3,1;
1,9,9,1;
1,29,72,29,1;
...
		

Crossrefs

Sum of k-th row is A006366(n). Columns give A006134, A006135, A006136.

Programs

  • Mathematica
    P[n_] := Table[Binomial[i + j - 2, i - 1], {i, 1, n}, {j, 1, n}];
    row[0] = {1};
    row[n_] := CoefficientList[ CharacteristicPolynomial[P[n], x], x] // Abs;
    Table[row[n], {n, 0, 9}] // Flatten (* Jean-François Alcover, Aug 09 2018 *)
  • PARI
    T(n,k)=if(n<0,0,(-1)^(n+k)*polcoeff(charpoly(matrix(n,n,i,j,binomial(i+j-2,i-1))),k))
    
  • PARI
    T(n,k)=if(n<0,0,polcoeff(charpoly(-matrix(n,n,i,j,binomial(i+j-2,i-1))),k))