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.

A267245 T(n,k)=Number of nXk binary arrays with row sums nondecreasing and columns lexicographically nondecreasing.

Original entry on oeis.org

2, 3, 3, 4, 7, 4, 5, 13, 15, 5, 6, 22, 42, 31, 6, 7, 34, 105, 141, 63, 7, 8, 50, 232, 567, 486, 127, 8, 9, 70, 475, 1986, 3351, 1685, 255, 9, 10, 95, 904, 6292, 20040, 20676, 5804, 511, 10, 11, 125, 1632, 18205, 107015, 220235, 129129, 19769, 1023, 11, 12, 161, 2806
Offset: 1

Views

Author

R. H. Hardin, Jan 12 2016

Keywords

Comments

Table starts
..2....3......4........5..........6............7..............8
..3....7.....13.......22.........34...........50.............70
..4...15.....42......105........232..........475............904
..5...31....141......567.......1986.........6292..........18205
..6...63....486.....3351......20040.......107015.........516084
..7..127...1685....20676.....220235......2093467.......17892539
..8..255...5804...129129....2499080.....43555569......683027146
..9..511..19769...804817...28501471....924051709....27044976947
.10.1023..66544..4982759..323067002..19614050515..1079112886476
.11.2047.221581.30629206.3626695952.413556580944.42860145907558

Examples

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

Crossrefs

Column 1 and row 1 are A000027(n+1).
Column 2 is A000225(n+1).
Row 2 is A002623.
Row 3 is A233302(n-1).
Row 4 is A233303(n-1).

Formula

Empirical for column k:
k=1: a(n) = 2*a(n-1) -a(n-2)
k=2: a(n) = 3*a(n-1) -2*a(n-2)
k=3: a(n) = 10*a(n-1) -39*a(n-2) +76*a(n-3) -79*a(n-4) +42*a(n-5) -9*a(n-6)
k=4: [order 10]
k=5: [order 14]
k=6: [order 22]
k=7: [order 32]
Empirical for row n:
n=1: a(n) = 2*a(n-1) -a(n-2)
n=2: a(n) = 3*a(n-1) -2*a(n-2) -2*a(n-3) +3*a(n-4) -a(n-5)
n=3: [order 13]