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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. 6
16, 150, 1080, 6627, 36552, 187000, 905440, 4206453, 18933408, 83153850, 358250280, 1520208679, 6373759384, 26468569500, 109080982800, 446806304505, 1821267503280, 7395000190750, 29933239010200, 120863093617131 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Column 2 of A223071.
LINKS
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
KEYWORD
nonn
AUTHOR
R. H. Hardin; Mar 14 2013
STATUS
approved

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Last modified April 14 16:33 EDT 2024. Contains 371666 sequences. (Running on oeis4.)