A223069 Number of n X 2 0..3 arrays with successive rows and columns fitting to straight lines with nondecreasing slope, with a single point array taken as having zero slope.

16, 150, 1080, 6627, 36552, 187000, 905440, 4206453, 18933408, 83153850, 358250280, 1520208679, 6373759384, 26468569500, 109080982800, 446806304505, 1821267503280, 7395000190750, 29933239010200, 120863093617131

Offset

1,1

Comments

Column 2 of A223071.

Links

R. H. Hardin, Table of n, a(n) for n = 1..41

Formula

Empirical: a(n) = 16*a(n-1) -106*a(n-2) +376*a(n-3) -769*a(n-4) +904*a(n-5) -564*a(n-6) +144*a(n-7).

Empirical g.f.: x*(16 - 106*x + 376*x^2 - 769*x^3 + 904*x^4 - 564*x^5 + 144*x^6) / ((1 - x)^2*(1 - 2*x)^2*(1 - 3*x)^2*(1 - 4*x)). - Colin Barker, Feb 18 2018

Example

Some solutions for n=3:
..2..1....2..2....3..1....3..3....2..0....2..2....3..0....3..2....1..1....2..0
..1..2....2..2....2..2....3..3....2..1....2..2....3..2....3..2....2..3....3..2
..0..2....2..2....0..2....0..3....3..2....3..3....0..3....0..0....0..1....1..1

Crossrefs

Sequence in context: A155657 A135458 A000486 * A006420 A221422 A049351

Adjacent sequences: A223066 A223067 A223068 * A223070 A223071 A223072

Keyword

nonn

Author

R. H. Hardin; Mar 14 2013

Status

approved