A183995 - OEIS

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A183995

Number of (n+1) X 2 0..2 arrays with all 2 X 2 subblock sums the same.

81, 171, 361, 855, 2025, 5175, 13225, 35535, 95481, 265431, 737881, 2100255, 5978025, 17298375, 50055625, 146516175, 428862681, 1265299191, 3733087801, 11073888255, 32849750025, 97806145575, 291205933225, 869194951215

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Column 1 of A184003.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n) = 6*a(n-1) - 60*a(n-3) + 85*a(n-4) + 150*a(n-5) - 360*a(n-6) + 396*a(n-8) - 216*a(n-9).

Empirical g.f.: x*(81 - 315*x - 665*x^2 + 3549*x^3 + 270*x^4 - 12000*x^5 + 6300*x^6 + 12420*x^7 - 9720*x^8) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 2*x^2)*(1 - 3*x^2)*(1 - 6*x^2)). - Colin Barker, Apr 09 2018

EXAMPLE

Some solutions for 3 X 2:

..0..1....1..1....0..1....2..1....0..1....0..2....2..1....2..1....2..0....2..0

..0..0....0..1....1..1....1..2....2..0....0..2....2..1....2..1....0..2....0..1

..1..0....2..0....1..0....2..1....1..0....0..2....2..1....1..2....2..0....2..0

CROSSREFS

Cf. A184003.

Sequence in context: A232923 A250655 A184003 * A044413 A044794 A350198

Adjacent sequences: A183992 A183993 A183994 * A183996 A183997 A183998

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 08 2011

STATUS

approved