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.

Showing 1-3 of 3 results.

A067323 Catalan triangle A028364 with row reversion.

Original entry on oeis.org

1, 2, 1, 5, 3, 2, 14, 9, 7, 5, 42, 28, 23, 19, 14, 132, 90, 76, 66, 56, 42, 429, 297, 255, 227, 202, 174, 132, 1430, 1001, 869, 785, 715, 645, 561, 429, 4862, 3432, 3003, 2739, 2529, 2333, 2123, 1859, 1430, 16796, 11934, 10504, 9646, 8986, 8398, 7810, 7150, 6292, 4862
Offset: 0

Views

Author

Wolfdieter Lang, Feb 05 2002

Keywords

Comments

a(N,p) equals X_{N}(N+1,p) := T_{N,p} for alpha= 1 =beta and N>=p>=1 in the Derrida et al. 1992 reference. The one-point correlation functions A000108(n)%20(Catalan)%20in%20this%20reference.%20See%20also%20the%20Derrida%20et%20al.%201993%20reference.%20In%20the%20Liggett%201999%20reference%20mu">{N} for alpha= 1 =beta equal a(N,K)/C(N+1) with C(n)=A000108(n) (Catalan) in this reference. See also the Derrida et al. 1993 reference. In the Liggett 1999 reference mu{N}{eta:eta(k)=1} of prop. 3.38, p. 275 is identical with _{N} and rho=0 and lambda=1.
Identity for each row n>=1: a(n,m)+a(n,n-m+1)= C(n+1), with C(n+1)=A000108(n+1)(Catalan) for every m=1..floor((n+1)/2). E.g., a(2k+1,k+1)=C(2*(k+1)).
The first column sequences (diagonals of A028364) are: A000108(n+1), A000245, A067324-6 for m=0..4.

Examples

			Triangle begins:
     1;
     2,    1;
     5,    3,    2;
    14,    9,    7,    5;
    42,   28,   23,   19,   14;
   132,   90,   76,   66,   56,   42;
   429,  297,  255,  227,  202,  174,  132;
  1430, 1001,  869,  785,  715,  645,  561,  429;
  4862, 3432, 3003, 2739, 2529, 2333, 2123, 1859, 1430;
  ...
		

References

  • B. Derrida, E. Domany and D. Mukamel, An exact solution of a one-dimensional asymmetric exclusion model with open boundaries, J. Stat. Phys. 69, 1992, 667-687; eqs. (19) - (23), p. 672.
  • B. Derrida, M. R. Evans, V. Hakim and V. Pasquier, Exact solution of a 1D asymmetric exclusion model using a matrix formulation, J. Phys. A 26, 1993, 1493-1517; eqs. (43), (44), pp. 1501-2 and eq.(81) with eqs.(80) and (81).
  • T. M. Liggett, Stochastic Interacting Systems: Contact, Voter and Exclusion Processes, Springer, 1999, pp. 269, 275.
  • G. Schuetz and E. Domany, Phase Transitions in an Exactly Soluble one-Dimensional Exclusion Process, J. Stat. Phys. 72 (1993) 277-295, eq. (2.18), p. 283, with eqs. (2.13)-(2.15).

Crossrefs

Cf. A001700 (row sums).
T(2n,n) gives A201205.

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0, 1, add(
          expand(b(n-1, j)*`if`(i>n, x, 1)), j=1..i))
        end:
    T:= n-> (p-> seq(coeff(p, x, n-i), i=0..n))(b((n+1)$2)):
    seq(T(n), n=0..10);  # Alois P. Heinz, Nov 28 2015
  • Mathematica
    t[n_, k_] := Sum[ CatalanNumber[n - j]*CatalanNumber[j], {j, 0, k}]; Flatten[ Table[t[n, k], {n, 0, 9}, {k, n, 0, -1}]] (* Jean-François Alcover, Jul 17 2013 *)

Formula

a(n,m) = A028364(n,n-m), n>=m>=0, else 0.
G.f. for column m>=1 (without leading zeros): (c(x)^3)sum(C(m-1, k)*c(x)^k, k=0..m-1), with C(n, m) := (m+1)*binomial(2*n-m, n-m)/(n+1) (Catalan convolutions A033184); and for m=0: c^2(x), where c(x) is g.f. of A000108 (Catalan).
T(n,k) = Sum_{j>=0} A039598(n-k,j)*A039599(k,j). - Philippe Deléham, Feb 18 2004
G.f. for diagonal sequences: see g.f. for columns of A028364.

A067325 Fourth column of triangle A067323.

Original entry on oeis.org

5, 19, 66, 227, 785, 2739, 9646, 34268, 122706, 442510, 1605956, 5861481, 21502585, 79243395, 293246550, 1089264360, 4059928950, 15179606010, 56917649820, 213982542150, 806429435994, 3046017513198
Offset: 0

Views

Author

Wolfdieter Lang, Feb 05 2002

Keywords

Comments

Also fourth diagonal of triangle A028364.

Crossrefs

Cf. A067324 (third column).

Formula

a(n)= A067323(n+3, 3)= C(n+4)-(C(n+3)+C(n+2)+2*C(n+1)), C(n) := A000108(n) (Catalan).
G.f.: (c(x)^3)*(2+2*c(x)+c(x)^2), with c(x) g.f. of A000108 (Catalan).

A287548 Triangle read by rows: T(n,k), where each row begins with the Catalan number for n nonintersecting arches and transitions through k generations of eliminating and reducing arch configurations to an end row entry equal to number of semi-meander solutions for n arches.

Original entry on oeis.org

1, 2, 1, 5, 3, 2, 14, 9, 7, 4, 42, 28, 23, 16, 10, 132, 90, 76, 57, 42, 24, 429, 297, 255, 199, 156, 108, 66, 1430, 1001, 869, 695, 563, 420, 304, 174, 4862, 3432, 3003, 2442, 2019, 1568, 1210, 836, 504
Offset: 1

Views

Author

Roger Ford, May 26 2017

Keywords

Examples

			Triangle begins:
n\k    1    2    3    4    5    6    7    8
1:     1
2:     2    1
3:     5    3    2
4:     14   9    7    4
5:     42   28   23   16   10
6:     132  90   76   57   42   24
7:     429  297  255  199  156  108  66
8:     1430 1001 869  695  563  420  304  174
...
Capital letters (U,D) represent beginning and end of first and last arch. Only 1 UD ends arch sequence in next generation.
Reduction of arches:            Elimination of arches:
(middle D U = new arch U D in the next arch generation)
            /\
     /\    //\\                      /\/\/\/\  = UDududUD
    //\\/\///\\\  = UudDudUuuddD        /\
        /\  /\                         /  \
     /\//\\//\\   =  UDuuddUudD       //\/\\   =  UududD
                                        end
For n=3 C(n)=5  nonintersecting arch configurations:
   UuuddD   UududD   UudDUD   UDUudD   UDudUD   T(3,1)=5
    end      end      UDUD     UDUD     UudD    T(3,2)=3
                       UD       UD       end    T(3,3)=2
		

Crossrefs

Formula

T(n,1) = Catalan Numbers C(n)= A000108(n).
Conjectured:
T(n,2) = C(n) - C(n-1) = A000245(n-1).
T(n,3) = C(n) - C(n-1) - C(n-2) = A067324(n-3).
T(n,4) = C(n) - C(n-1) - 2*C(n-2) - C(n-3).
T(n,n) = semi-meander solutions = A000682(n-1).
Showing 1-3 of 3 results.