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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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

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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.
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