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.

A091962 From enumerating paths in the plane.

Original entry on oeis.org

0, 1, 42, 594, 4719, 26026, 111384, 395352, 1215126, 3331251, 8321170, 19240650, 41683005, 85408596, 166768096, 312203232, 563178924, 982981701, 1665911754, 2749500754, 4430505387, 6985558206, 10797503640, 16388608600, 24462014850, 35952994935, 52091785746
Offset: 0

Views

Author

Philippe Deléham, Mar 13 2004

Keywords

Comments

a(n+1) is the determinant of the n X n Hankel matrix [C(i+j+3)]A000108(n),%20the%20n-th%20Catalan%20number.%20-%20_Michael%20Somos">{i,j=1..n} where C(n) = A000108(n), the n-th Catalan number. - _Michael Somos, Jun 27 2023

Examples

			G.f. = x + 42*x^2 + 594*x^3 + 4719*x^4 + 26026*x^5 + 111384*x^6 + ... - _Michael Somos_, Jun 27 2023
		

References

  • R. P. Stanley, Enumerative Combinatorics, volume 1 (1986), p. 221, Example 4.5.18.

Crossrefs

Cf. A000108.
Cf. A000012, A000027, A000330, A006858 (Hankel determinants of Catalan numbers). - Michael Somos, Jun 27 2023

Programs

  • Mathematica
    LinearRecurrence[{11,-55,165,-330,462,-462,330,-165,55,-11,1},{0,1,42,594,4719,26026,111384,395352,1215126,3331251,8321170},30] (* Harvey P. Dale, Apr 15 2017 *)
  • PARI
    a(n) = binomial(2*n+6, 7)*(2*n+3)*(n+1)*(n+2)/240; \\ Michel Marcus, Oct 13 2016
    
  • Sage
    [product(binomial(2*(n+j+2), 4*j+3) for j in (0..1))/160 for n in (0..30)] # G. C. Greubel, Dec 17 2021

Formula

a(n) = binomial(2*n+6, 7)*(2*n+3)*(n+1)*(n+2)/240.
G.f.: x*(1 + 31*x + 187*x^2 + 330*x^3 + 187*x^4 + 31*x^5 + x^6)/(1-x)^11. - Colin Barker, May 07 2012
a(n) = det(A*Transpose(A))/36, where A is the 2 X (n+1) matrix whose (i,j)-th element is j^(2*i-1). - Lechoslaw Ratajczak, Oct 01 2017
a(n) = binomial(2*n+4, 3)*binomial(2*n+6, 7)/160. - G. C. Greubel, Dec 17 2021
a(n) = a(-3-n) for all n in Z. - Michael Somos, Jun 27 2023
a(n) ~ n^10/4725. - Stefano Spezia, Dec 09 2023