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.

A178107 Coefficient array for orthogonal polynomials P(n,x)=x*P(n-1,x)-(2*floor((n+2)/2)-3)*P(n-2,x), P(0,x)=1,P(1,x)=x.

Original entry on oeis.org

1, 0, 1, -1, 0, 1, 0, -2, 0, 1, 3, 0, -5, 0, 1, 0, 9, 0, -8, 0, 1, -15, 0, 34, 0, -13, 0, 1, 0, -60, 0, 74, 0, -18, 0, 1, 105, 0, -298, 0, 165, 0, -25, 0, 1, 0, 525, 0, -816, 0, 291, 0, -32, 0, 1, -945, 0, 3207, 0, -2301, 0, 516, 0, -41, 0, 1, 0, -5670, 0, 10551, 0, -4920, 0, 804, 0
Offset: 0

Views

Author

Paul Barry, May 20 2010

Keywords

Comments

Inverse is A178108. First column is signed aerated version of double factorials A001147.

Examples

			Triangle begins
1,
0, 1,
-1, 0, 1,
0, -2, 0, 1,
3, 0, -5, 0, 1,
0, 9, 0, -8, 0, 1,
-15, 0, 34, 0, -13, 0, 1,
0, -60, 0, 74, 0, -18, 0, 1,
105, 0, -298, 0, 165, 0, -25, 0, 1,
0, 525, 0, -816, 0, 291, 0, -32, 0, 1,
-945, 0, 3207, 0, -2301, 0, 516, 0, -41, 0, 1
Production matrix is
0, 1,
-1, 0, 1,
0, -1, 0, 1,
1, 0, -3, 0, 1,
0, 1, 0, -3, 0, 1,
2, 0, 1, 0, -5, 0, 1,
0, 2, 0, 1, 0, -5, 0, 1,
7, 0, 2, 0, 1, 0, -7, 0, 1,
0, 7, 0, 2, 0, 1, 0, -7, 0, 1
Production matrix of inverse is
0, 1,
1, 0, 1,
0, 1, 0, 1,
0, 0, 3, 0, 1,
0, 0, 0, 3, 0, 1,
0, 0, 0, 0, 5, 0, 1,
0, 0, 0, 0, 0, 5, 0, 1,
0, 0, 0, 0, 0, 0, 7, 0, 1,
0, 0, 0, 0, 0, 0, 0, 7, 0, 1
		

Programs

  • Mathematica
    p[0] = 1; p[1] = x;
    p[n_] := p[n] = Expand[x p[n-1] - (2 Quotient[n+2, 2] - 3) p[n-2]];
    Table[CoefficientList[p[n], x], {n, 0, 6}] (* Andrey Zabolotskiy, Dec 26 2023 *)