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A206231 Number of (n+1) X 2 0..3 arrays with every 2 X 3 or 3 X 2 subblock having exactly two equal edges, and new values 0..3 introduced in row major order. 1
15, 60, 310, 1640, 8910, 51066, 294546, 1710184, 10051522, 59273370, 350336326, 2076929912, 12328636710, 73241168202, 435453806538, 2590088923960, 15409982499130, 91703551575882, 545793722630878, 3248685323916392 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A206238.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 8*a(n-1) -11*a(n-2) +36*a(n-3) -303*a(n-4) +232*a(n-5) +147*a(n-6) +756*a(n-7) for n>8.

Empirical g.f.: x*(15 - 60*x - 5*x^2 - 720*x^3 + 1585*x^4 + 1366*x^5 + 2793*x^6 - 378*x^7) / ((1 - 4*x)*(1 - x - x^2 - 3*x^3)*(1 - 3*x - 7*x^2 - 63*x^3)). - Colin Barker, Jun 14 2018

EXAMPLE

Some solutions for n=4:

..0..1....0..0....0..1....0..0....0..0....0..1....0..1....0..0....0..0....0..0

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

..0..1....1..2....0..1....1..0....0..1....3..1....0..0....2..1....1..2....1..2

..1..2....1..1....1..0....0..0....0..0....0..1....3..0....1..0....2..2....1..1

..1..1....0..1....0..0....2..2....0..2....3..3....2..1....0..0....1..1....0..0

CROSSREFS

Cf. A206238.

Sequence in context: A005945 A223337 A110755 * A001756 A284096 A022288

Adjacent sequences:  A206228 A206229 A206230 * A206232 A206233 A206234

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 05 2012

STATUS

approved

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Last modified February 19 22:04 EST 2020. Contains 332060 sequences. (Running on oeis4.)