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.

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A064308 Product of two triangular matrices C*S2.

Original entry on oeis.org

1, 4, 2, 13, 20, 5, 41, 149, 98, 14, 131, 1022, 1330, 462, 42, 428, 6866, 15768, 9990, 2112, 132, 1429, 46188, 176229, 181170, 66792, 9438, 429, 4861, 313601, 1917960, 3003990, 1717287, 411411, 41470, 1430
Offset: 1

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Author

Wolfdieter Lang, Sep 13 2001

Keywords

Comments

This triangular matrix appears in the definition of the row polynomials for triangle A064307.
The first column sequence (m=1) gives A001453(n+1). The main diagonal gives A000108(n+1). Row sums give A064309.

Formula

a(n, m)=sum(A009766(n, k)*A008277(k, m), k=m..n), n >= m >= 1 else 0. Product of Catalan triangular matrix (without row n=0 and column m=0) with Stirling2 triangular matrix.

A115126 First (k=1) triangle of numbers related to totally asymmetric exclusion process (case alpha=1, beta=1).

Original entry on oeis.org

1, 2, 2, 3, 5, 5, 4, 9, 14, 14, 5, 14, 28, 42, 42, 6, 20, 48, 90, 132, 132, 7, 27, 75, 165, 297, 429, 429, 8, 35, 110, 275, 572, 1001, 1430, 1430, 9, 44, 154, 429, 1001, 2002, 3432, 4862, 4862, 10, 54, 208, 637, 1638, 3640, 7072, 11934, 16796, 16796, 11, 65, 273, 910
Offset: 1

Views

Author

Wolfdieter Lang, Jan 13 2006

Keywords

Comments

First (k=0) column removed from Catalan triangle A009766(n,k).
In the Derrida et al. 1992 reference this triangle, called here X(alpha=1,beta=1;k=1,n,m), n >= m >= 1, is called there X_{N=n}(K=1,p=m) with alpha=1 and beta=1.
The column sequences give A000027 (natural numbers), A000096, A005586, A005587, A005557, A064059, A064061 for m=1..7. The numerator polynomials for the o.g.f. of column m is found in A062991 and the denominator is (1-x)^(m+1).
The diagonal sequences are convolutions of the Catalan numbers A000108, starting with the main diagonal.

Examples

			[1];[2,2];[3,5,5];[4,9,14,14];...
a(4,2) = 9 = binomial(6,2)*3/5.
		

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. (20), (21), 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; eq. (39), p. 1501, also appendix A1, (A12) p. 1513.

Crossrefs

Row sums give A001453(n+1)=A000108(n+1)-1 (Catalan -1).

Formula

a(n, m)= binomial(n+m, n)*(n-m+1)/(n+1), n>=m>=1; a(n, m)=0 if n

A128634 Number of parallel permutations of length n.

Original entry on oeis.org

0, 2, 8, 26, 82, 262, 856, 2858, 9722, 33590, 117570, 416022, 1485798, 5348878, 19389688, 70715338, 259289578, 955277398, 3534526378, 13128240838, 48932534038, 182965127278, 686119227298, 2579808294646, 9723892802902, 36734706144302, 139067101832006, 527495903500718
Offset: 1

Author

Ralf Stephan, May 08 2007

Keywords

Crossrefs

Programs

  • GAP
    List([1..30], n-> 2*(Binomial(2*n, n)/(n+1) -1) ); # G. C. Greubel, Dec 02 2019
  • Magma
    [2*(Catalan(n)-1): n in [1..40]]; // Vincenzo Librandi, Jul 22 2015
    
  • Maple
    c:=binomial(2*n,n)/(n+1); seq(2*(c(n)-1), n=1..30); # G. C. Greubel, Dec 02 2019
  • Mathematica
    Table[2 (CatalanNumber[n] - 1), {n, 30}] (* Vincenzo Librandi, Jul 22 2015 *)
  • PARI
    vector(30, n, 2*(binomial(2*n,n)/(n+1) -1) ) \\ Michel Marcus, Jul 21 2015
    
  • Sage
    [2*(catalan_number(n) -1) for n in (1..30)] # G. C. Greubel, Dec 02 2019
    

Formula

a(n) = -2 + 2 * binomial(2*n,n)/(n+1).
a(n) = -2 + A068875(n+1).
a(n) = 2*A001453(n) for n > 1. - J. M. Bergot, Sep 03 2013
a(n)= Sum_{r=0..n} A214292(n, r)^2. - J. M. Bergot, Sep 04 2013

Extensions

More terms from Michel Marcus, Jul 21 2015
Offset changed by G. C. Greubel, Dec 02 2019

A141364 a(n) = C(n)-1+0^n where C(n) = A000108(n).

Original entry on oeis.org

1, 0, 1, 4, 13, 41, 131, 428, 1429, 4861, 16795, 58785, 208011, 742899, 2674439, 9694844, 35357669, 129644789, 477638699, 1767263189, 6564120419, 24466267019, 91482563639, 343059613649, 1289904147323, 4861946401451, 18367353072151
Offset: 0

Author

Paul Barry, Jun 27 2008

Keywords

Comments

Hankel transform is A141365.

Crossrefs

Cf. A000108, A001453 (essentially the same sequence), A141351.

Programs

  • Mathematica
    CoefficientList[Series[(1 - Sqrt[1 - 4*x]) / (2*x)-x/(1-x),{x,0,26}],x] (* James C. McMahon, Jul 23 2025 *)

Formula

G.f.: c(x)-x/(1-x) where c(x) is the g.f. of A000108

A239432 Number of permutations of length n with longest increasing subsequence of length 8.

Original entry on oeis.org

1, 64, 2521, 79861, 2250887, 59367101, 1508071384, 37558353900, 927716186325, 22904111472825, 568209449266202, 14216730315766814, 359666061054003144, 9216708503647774264, 239524408949706575548, 6317740398995612513164, 169207499997274346326579, 4602911809939402715164066
Offset: 8

Author

Vaclav Kotesovec, Mar 18 2014

Keywords

Comments

In general, for column k of A047874 is a(n) ~ product(j!, j=0..k-1) * k^(2*n+k^2/2) / (2^((k-1)*(k+2)/2) * Pi^((k-1)/2) * n^((k^2-1)/2)) [Regev, 1981].

Formula

a(n) ~ 1913625 * 2^(6*n+77) / (Pi^(7/2) * n^(63/2)).

A247493 Triangle read by rows: T(n, k) = C(n, k)*C(2*k, k)/(k+1) - sum(j = 0..k, (-1)^j*(1-j)^n*C(k, j)/k!), 0<=k<=n.

Original entry on oeis.org

0, 0, 0, 0, 1, 1, 0, 2, 6, 4, 0, 3, 11, 22, 13, 0, 4, 20, 45, 75, 41, 0, 5, 29, 110, 190, 261, 131, 0, 6, 42, 154, 560, 826, 938, 428, 0, 7, 55, 322, 749, 2646, 3570, 3452, 1429, 0, 8, 72, 335, 2499, 3885, 12012, 15198, 12897, 4861, 0, 9, 89, 770, 650, 16947, 21693, 53880, 63915, 48655, 16795, 0, 10, 110, 484, 11660, -8338, 97482
Offset: 0

Author

Peter Luschny, Oct 02 2014

Keywords

Comments

First negative value appears at T(11,5). - Indranil Ghosh, Mar 04 2017

Examples

			0;
0, 0;
0, 1, 1;
0, 2, 6, 4;
0, 3, 11, 22, 13;
0, 4, 20, 45, 75, 41;
0, 5, 29, 110, 190, 261, 131;
0, 6, 42, 154, 560, 826, 938, 428;
		

Crossrefs

Programs

  • Maple
    T := proc(n, k) binomial(n,k)*binomial(2*k,k)/(k+1) - add((-1)^j*(1-j)^n /(j!*(k-j)!), j = 0..k) end:
    for n from 0 to 12 do seq(T(n,k), k=0..n) od;
  • Mathematica
    Flatten[Table[(Binomial[n,k] * Binomial[2k,k] / (k+1)) - Sum[(-1)^j*(1-j)^n*Binomial[k,j]/k!,{j,0,k}],{n,0,10},{k,0,n}]] (* Indranil Ghosh, Mar 04 2017 *)
  • PARI
    tabl(nn) = {for (n=0, nn, for (k=0, n, print1((binomial(n,k)*binomial(2*k,k)/(k+1))-sum(j=0, k, (-1)^j*(1-j)^n*binomial(k,j)/k!),", ",);); print(););};
    tabl(10); \\ Indranil Ghosh, Mar 04 2017

Formula

A105794(n, k) = (-1)^(n-k)*(C(n, k)*Catalan(k) - T(n, k)).
A247491(n) = Sum(k=0..n, (-1)^(n-k+1)*T(n, k)).
A001453(n) = T(n, n).
T(n,k) = A098474 (n,k) - A105794 (n,k). - Michel Marcus, Mar 04 2017

A349740 Number of partitions of set [n] in a set of <= k noncrossing subsets. Number of Dyck n-paths with at most k peaks. Both with 0 <= k <= n, read by rows.

Original entry on oeis.org

1, 0, 1, 0, 1, 2, 0, 1, 4, 5, 0, 1, 7, 13, 14, 0, 1, 11, 31, 41, 42, 0, 1, 16, 66, 116, 131, 132, 0, 1, 22, 127, 302, 407, 428, 429, 0, 1, 29, 225, 715, 1205, 1401, 1429, 1430, 0, 1, 37, 373, 1549, 3313, 4489, 4825, 4861, 4862, 0, 1, 46, 586, 3106, 8398, 13690, 16210, 16750, 16795, 16796
Offset: 0

Author

Ron L.J. van den Burg, Nov 28 2021

Keywords

Comments

Given a partition P of the set {1,2,...,n}, a crossing in P are four integers [a, b, c, d] with 1 <= a < b < c < d <= n for which a, c are together in a block, and b, d are together in a different block. A noncrossing partition is a partition with no crossings.

Examples

			For n=4 the T(4,3)=13 partitions are {{1,2,3,4}}, {{1,2,3},{4}}, {{1,2,4},{3}}, {{1,3,4},{2}}, {{2,3,4},{1}}, {{1,2},{3,4}}, {{1,4},{2,3}}, {{1,2},{3},{4}}, {{1,3},{2},{4}}, {{1,4},{2},{3}}, {{1},{2,3},{4}}, {{1},{2,4},{3}}, {{1},{2},{3,4}}.
The set of sets {{1,3},{2,4}} is missing because it is crossing. If you add the set of 4 sets, {{1},{2},{3},{4}}, you get T(4, 4) = 14 = A000108(4), the 4th Catalan number.
Triangle begins:
  1;
  0, 1;
  0, 1,  2;
  0, 1,  4,   5;
  0, 1,  7,  13,   14;
  0, 1, 11,  31,   41,   42;
  0, 1, 16,  66,  116,  131,  132;
  0, 1, 22, 127,  302,  407,  428,  429;
  0, 1, 29, 225,  715, 1205, 1401, 1429, 1430;
  0, 1, 37, 373, 1549, 3313, 4489, 4825, 4861, 4862;
  ...
		

Crossrefs

Columns k=0-4 give (for n>=k): A000007, A000012, A000124(n-1), A116701, A116844.
Partial sums of A090181 per row.
Main diagonal is A000108.
Row sums give A088218.
T(2*n,n) gives A065097.
T(n,n-1) gives A001453 for n >= 2.

Programs

  • Maple
    b:= proc(x, y, t) option remember; expand(`if`(y<0
          or y>x, 0, `if`(x=0, 1, add(b(x-1, y+j, j)*
         `if`(t=1 and j<1, z, 1), j=[-1, 1]))))
        end:
    T:= proc(n, k) option remember; `if`(k<0, 0,
          T(n, k-1)+coeff(b(2*n, 0$2), z, k))
        end:
    seq(seq(T(n, k), k=0..n), n=0..10);  # Alois P. Heinz, Nov 28 2021
  • Mathematica
    T[n_, k_] := If[n == 0, 1, Sum[j Binomial[n, j]^2 / (n - j + 1), {j, 0, k}] / n];
    Table[T[n, k], {n, 0, 9}, {k, 0, n}] // Flatten (* Peter Luschny, Nov 29 2021 *)

Formula

T(n,k) = Sum_{j=0..k} A090181(n,j), the partial sum of the Narayana numbers.
T(n,n) = A000108(n), the n-th Catalan number.
G.f.: (1 + x - x*y - sqrt((1-x*(1+y))^2 - 4*y*x^2))/(2*x*(1-y)).
T(n,k) = (1/n)*Sum_{j=0..k} j*binomial(n,j)^2 / (n-j+1) for n >= 1. - Peter Luschny, Nov 29 2021

A097607 Triangle read by rows: T(n,k) is number of Dyck paths of semilength n and having leftmost valley at altitude k (if path has no valleys, then this altitude is considered to be 0).

Original entry on oeis.org

1, 1, 2, 4, 1, 9, 4, 1, 23, 13, 5, 1, 65, 41, 19, 6, 1, 197, 131, 67, 26, 7, 1, 626, 428, 232, 101, 34, 8, 1, 2056, 1429, 804, 376, 144, 43, 9, 1, 6918, 4861, 2806, 1377, 573, 197, 53, 10, 1, 23714, 16795, 9878, 5017, 2211, 834, 261, 64, 11, 1, 82500, 58785, 35072
Offset: 0

Author

Emeric Deutsch, Aug 30 2004

Keywords

Comments

Row sums are the Catalan numbers (A000108) Column 0 is A014137 (partial sums of Catalan numbers). Column 1 is A001453 (Catalan numbers -1).

Examples

			Triangle starts:
1;
1;
2;
4,1;
9,4,1;
23,13,5,1;
65,41,19,6,1;
T(4,1)=4 because we have UU(DU)DDUD, UU(DU)DUDD, UU(DU)UDDD and UUUD(DU)DD, where U=(1,1), D=(1,-1); the first valleys, all at altitude 1, are shown between parentheses.
		

Crossrefs

Formula

G.f.=(1-z+zC-tzC)/[(1-z)(1-tzC)], where C=[1-sqrt(1-4z)]/(2z) is the Catalan function.

A112307 Triangle read by rows: T(n,k) is number of Dyck paths of semilength n with height of second peak equal to k (n>=1; 0<=k<=n-1).

Original entry on oeis.org

1, 1, 1, 1, 2, 2, 1, 4, 6, 3, 1, 9, 16, 12, 4, 1, 23, 44, 39, 20, 5, 1, 65, 128, 123, 76, 30, 6, 1, 197, 392, 393, 268, 130, 42, 7, 1, 626, 1250, 1284, 928, 505, 204, 56, 8, 1, 2056, 4110, 4287, 3216, 1880, 864, 301, 72, 9, 1, 6918, 13834, 14583, 11224, 6885, 3438, 1379
Offset: 1

Author

Emeric Deutsch, Nov 30 2005

Keywords

Comments

Row sums are the Catalan numbers (A000108). T(n,0)=1 (paths have only one peak); The g.f. for column k is kz^(k+1)*c^k/(1-z), where c=[1-sqrt(1-4z)]/(2z) is the Catalan function. T(n,1)=A014137(n-1); T(n,2)=2*A014138(n-3); T(n,3)=3*A001453(n-2); T(n,4)=4*A114277(n-5); Sum(k*T(n,k), k=0..n-1)=A112308(n-2).

Examples

			T(4,1)=4 because we have UDUDUDUD, UDUDUUDD, UUDDUDUD and UUUDDDUD, where U=(1,1), D=(1,-1).
Triangle begins:
1;
1,1;
1,2,2;
1,4,6,3;
1,9,16,12,4;
		

Programs

  • Maple
    G:=((1-t*z*c)^2+t*z^2*c)/(1-z)/(1-t*z*c)^2-1: c:=(1-sqrt(1-4*z))/2/z: Gser:=simplify(series(G,z=0,15)): for n from 1 to 12 do P[n]:=coeff(Gser,z^n) od: for n from 1 to 12 do seq(coeff(t*P[n],t^j),j=1..n) od; # yields sequence in triangular form

Formula

G.f.=[(1-tzc)^2+tz^2*c]/[(1-z)(1-tzc)^2]-1, where c=[1-sqrt(1-4z)]/(2z) is the Catalan function.

A114276 Triangle read by rows: T(n,k) is the number of Dyck paths of semilength n having length of second ascent equal to k (0<=k<=n-1).

Original entry on oeis.org

1, 1, 1, 1, 3, 1, 1, 8, 4, 1, 1, 22, 13, 5, 1, 1, 64, 41, 19, 6, 1, 1, 196, 131, 67, 26, 7, 1, 1, 625, 428, 232, 101, 34, 8, 1, 1, 2055, 1429, 804, 376, 144, 43, 9, 1, 1, 6917, 4861, 2806, 1377, 573, 197, 53, 10, 1, 1, 23713, 16795, 9878, 5017, 2211, 834, 261, 64, 11, 1, 1
Offset: 1

Author

Emeric Deutsch, Nov 20 2005

Keywords

Comments

Column 1 yields A014138, column 2 yields A001453, column 3 yields A114277. Row sums are the Catalan numbers (A000108).

Examples

			T(4,2)=4 because we have UD(UU)DDUD, UD(UU)DUDD, UUD(UU)DDD and UUDD(UU)DD (second ascent shown between parentheses).
		

Crossrefs

Programs

  • Maple
    T:=proc(n,k) if k=0 then 1 elif k<=n-1 then (k+1)*sum(binomial(2*n-k+1-2*j,n-j+1)/(2*n-k-2*j+1),j=1..n-k) else 0 fi end: for n from 1 to 12 do seq(T(n,k),k=0..n-1) od; # yields sequence in triangular form

Formula

T(n, k)=(k+1)*sum(binomial(2*n-k+1-2*j, n-j+1)/(2*n-k-2*j+1), j=1..n-k) if 1<=k<=n-1; T(n, 0)=1. G.f. = (1-tz)/[(1-z)(1-tzC)]-1 where C=[1-sqrt(1-4z)]/(2z) is the Catalan function.
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