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.

A229774 T(n,k)=Number of n X n 0..k arrays with rows in lexicographically nondecreasing order and columns in nonincreasing order.

Original entry on oeis.org

2, 3, 6, 4, 22, 20, 5, 60, 322, 70, 6, 135, 3232, 12958, 252, 7, 266, 21331, 1058494, 2179956, 924, 8, 476, 103222, 35452250, 3062815568, 1976588468, 3432, 9, 792, 397460, 637396928, 843211336888, 90462380211862, 10811999412826, 12870, 10
Offset: 1

Views

Author

R. H. Hardin, Sep 29 2013

Keywords

Comments

Table starts
...2..........3..............4..................5.....................6
...6.........22.............60................135...................266
..20........322...........3232..............21331................103222
..70......12958........1058494...........35452250.............637396928
.252....2179956.....3062815568.......843211336888........81937334158292
.924.1976588468.90462380211862.322942973130396495.245200063296427870294

Examples

			Some solutions for n=3 k=4
..2..2..0....3..3..3....2..1..1....1..0..0....1..1..0....2..0..0....2..2..2
..3..0..0....4..0..0....3..0..0....1..3..0....3..0..3....2..2..2....3..3..1
..4..3..3....4..2..0....3..4..4....2..4..1....4..4..1....2..2..2....4..4..0
		

Crossrefs

Column 1 is A000984
Row 1 is A000027(n+1)
Row 2 is A071239(n+1)

Formula

Empirical for row n:
n=1: a(n) = n + 1
n=2: a(n) = (1/6)*n^4 + (5/6)*n^3 + (11/6)*n^2 + (13/6)*n + 1
n=3: [polynomial of degree 9]
n=4: [polynomial of degree 16]