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.

A064334 Triangle composed of generalized Catalan numbers.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, -1, 1, 1, 1, -2, 5, -2, 1, 1, 1, 6, -25, 13, -3, 1, 1, 1, -18, 141, -98, 25, -4, 1, 1, 1, 57, -849, 826, -251, 41, -5, 1, 1, 1, -186, 5349, -7448, 2817, -514, 61, -6, 1, 1, 1, 622, -34825, 70309, -33843, 7206, -917, 85, -7, 1, 1
Offset: 0

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Author

Wolfdieter Lang, Sep 21 2001

Keywords

Comments

The sequence for column m (m >= 1) (without leading zeros and the first 1) appears in the Derrida et al. 1992 reference as Z_{N}=:Y_{N}(N+1), N >=0, for (unphysical) alpha = -m, beta = 1 (or alpha = 1, beta = -m). In the Derrida et al. 1993 reference the formula in eq. (39) gives Z_{N}(alpha,beta)/(alpha*beta)^N for N>=1. See also Liggett reference, proposition 3.19, p. 269, with lambda for alpha and rho for 1-beta.

Examples

			Triangle starts:
  1;
  1,  1;
  1,  1,  1;
  1,  0,  1,  1;
  1,  1, -1,  1, 1;
  1, -2,  5, -2, 1, 1; ...
		

References

  • T. M. Liggett, Stochastic Interacting Systems: Contact, Voter and Exclusion Processes, Springer, 1999, p. 269.

Crossrefs

The unsigned column sequences (without leading zeros) are A000012, A064310-11, A064325-33 for m=0..11, respectively. Row sums (signed) give A064338. Row sums (unsigned) give A064339.
Cf. A064062.

Programs

  • Magma
    [[k eq 0 select 1 else k eq n select 1 else (&+[(n-k-j)* Binomial(n-k-1+j, j)*(-k)^j/(n-k): j in [0..n-k-1]]): k in [0..n]]: n in [0..12]]; // G. C. Greubel, May 04 2019
  • Mathematica
    Table[If[k==0, 1, If[k==n, 1, Sum[(n-k-j)*Binomial[n-k-1+j, j]*(-k)^j/(n -k), {j, 0, n-k-1}]]], {n, 0, 12}, {k, 0, n}]//Flatten (* G. C. Greubel, May 04 2019 *)
  • PARI
    {T(n,k) = if(k==0, 1, if(k==n, 1, sum(j=0, n-k-1, (n-k-j)* binomial(n-k-1+j, j)*(-k)^j/(n-k))))}; \\ G. C. Greubel, May 04 2019
    
  • Sage
    def T(n,k):
        return hypergeometric([1-n, n], [-n], -k) if n>0 else 1
    for n in (0..10):
        print([simplify(T(n-k,k)) for k in (0..n)]) # Peter Luschny, Nov 30 2014
    

Formula

G.f. for column m: (x^m)/(1-x*c(-m*x))= (x^m)*((m+1)+m*x*c(-m*x))/((m+1)-x), m>0, with the g.f. c(x) of Catalan numbers A000108.
T(n, m) = Sum_{k=0..n-m-1} (n-m-k)*binomial(n-m-1+k, k)*(-m)^k/(n-m), with T(n,0) = T(n,n)=1.
T(n,m) = (1/(1+m))^(n-m)*(1 + m*Sum_{k=0..n-m-1} C(k)*(-m*(m+1))^k ), n-m >= 1, T(n, n) = T(n,0) =1, T(n, m)=0 if nA000108(k) (Catalan).
T(n, k) = hypergeometric([1-n+k, n-k], [-n+k], -k) if kPeter Luschny, Nov 30 2014