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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A028376 Triangle read by rows: T(n,m) = Sum Catalan(n-k)*Catalan(k), k=0..m.

Original entry on oeis.org

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

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Author

Keywords

Examples

			0;
0,1;
0,1,2;
0,2,3,5;
0,5,7,9,14;
0,14,19,23,28,42; ...
		

Crossrefs

See A028364 for a better version. Cf. A028377, A028378.

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).

A067326 Fifth column of triangle A067323.

Original entry on oeis.org

14, 56, 202, 715, 2529, 8986, 32123, 115556, 418200, 1521976, 5567551, 20462525, 75528895, 279874350, 1040790135, 3883140600, 14531382060, 54529456320, 205146226200, 773608833894, 2923686178098, 11071970477876
Offset: 0

Views

Author

Wolfdieter Lang, Feb 05 2002

Keywords

Comments

Also fifth diagonal of triangle A028364.

Crossrefs

Cf. A067325 (fourth column).

Formula

a(n)= A067323(n+4, 4)= C(n+5)-sum(C(k)*C(n+4-k), k=0..3), C(n) := A000108(n) (Catalan).
G.f.: (c(x)^3)*(5+5*c(x)+3*c(x)^2+c(x)^3), with c(x) g.f. of A000108 (Catalan).

A073147 Triangle of numbers {a(n,k), n >= 0, 0<=k<=n} defined by a(0,0)=1, a(n,0)=A001764(n), a(n,n)=A006013(n), a(n,n-1)=A006629(n-1).

Original entry on oeis.org

1, 1, 2, 3, 4, 7, 12, 15, 18, 30, 55, 67, 76, 88, 143, 273, 328, 364, 400, 455, 728, 1428, 1701, 1866, 2010, 2175, 2448, 3876, 7752, 9180, 9999, 10659, 11319, 12138, 13566, 21318, 43263
Offset: 0

Views

Author

Paul D. Hanna, Jul 18 2002

Keywords

Comments

Related to generalized Catalan numbers; in particular, C(3n,n)/(2n+1) (enumerates ternary trees and also non-crossing trees)(A001764) and sum of root degrees of all noncrossing trees on nodes on a circle (A006629).
These numbers are cardinalities of some intervals in the Tamari lattices. - F. Chapoton, Jul 15 2021

Examples

			{1}, {1,2}, {3,4,7}, {12,15,18,30}, {55,67,76,88,143}, {273,328,364,400,455,728},...
		

Crossrefs

Formula

(n, m)-th entry in triangle is Sum A001764(n-k)*A001764(k), k=0..m.

A073148 Triangle of numbers {a(n,k), n >= 0, 0<=k<=n} defined by a(0,0)=1, a(n,0)=A006013(n), a(n+1,n)=A001764(n+1), a(n,m) = Sum A001764(n-k)*a(n,k), k=0..m.

Original entry on oeis.org

1, 2, 3, 7, 9, 12, 30, 37, 43, 55, 143, 173, 194, 218, 273, 728, 871, 961, 1045, 1155, 1428, 3876, 4604, 5033, 5393, 5778, 6324, 7752, 21318, 25194, 27378, 29094, 30744, 32655, 35511, 43263, 120175
Offset: 0

Views

Author

Paul D. Hanna, Jul 18 2002

Keywords

Comments

Compare to A073147. Related to generalized Catalan numbers; in particular, C(3n,n)/(2n+1) (enumerates ternary trees and also non-crossing trees)(A001764).
These numbers are cardinalities of some intervals in the Tamari lattices. - F. Chapoton, Jul 15 2021

Examples

			{1}, {2,3}, {7,9,12}, {30,37,43,55}, {143,173,194,218,273},{728,871,961,1045,1155,1428}, {3876,4604,5033,5393,5778,6324,7752}, ...
		

Crossrefs

Formula

a(n, m) = Sum A001764(n-k)*a(n, k), k=0..m.

A116871 Sixth column of triangle A067323.

Original entry on oeis.org

42, 174, 645, 2333, 8398, 30275, 109550, 398180, 1453908, 5332407, 19639521, 72616727, 269473750, 1003347975, 3747412770, 14036374680, 52714429260, 198459284400, 748867149234, 2831788492218, 10729442739596
Offset: 0

Views

Author

Wolfdieter Lang, Mar 24 2006

Keywords

Comments

Also sixth diagonal sequence of triangle A028364.

Crossrefs

Cf. A067326 (fifth column of A067323).

Formula

a(n)= A067323(n+5,5), n>=0.
a(n)= A028364(5+n,n) = sum(C(k)*C(5+n-k),k=0..n), n>=0, with the Catalan numbers C(n):=A000108(n).
G.f.: (c(x)^3)sum(C(4, k)*c(x)^k, k=0..4), with C(n, m) := (m+1)*binomial(2*n-m, n-m)/(n+1) (Catalan convolutions A033184).
Previous Showing 21-26 of 26 results.