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A208086 Number of 4 X (n+1) 0..1 arrays with every 2 X 2 subblock having the same number of equal edges as its horizontal neighbors and a different number from its vertical neighbors, and new values 0..1 introduced in row major order. 1
24, 56, 134, 344, 888, 2318, 6056, 15848, 41478, 108584, 284264, 744206, 1948344, 5100824, 13354118, 34961528, 91530456, 239629838, 627359048, 1642447304, 4299982854, 11257501256, 29472520904, 77160061454, 202007663448 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 3 of A208085.

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) - 3*a(n-3) + a(n-4).

Conjectures from Colin Barker, Jun 27 2018: (Start)

G.f.: 2*x*(12 - 8*x - 17*x^2 + 7*x^3) / ((1 - x)*(1 + x)*(1 - 3*x + x^2)).

a(n) = 2^(1-n)*(2^n*(15+2*(-1)^n) + (9-4*sqrt(5))*(3-sqrt(5))^n + (3+sqrt(5))^n*(9+4*sqrt(5))) / 5.

(End)

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Cf. A208085.

Sequence in context: A043198 A043978 A211461 * A232937 A190104 A255968

Adjacent sequences:  A208083 A208084 A208085 * A208087 A208088 A208089

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 23 2012

STATUS

approved

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Last modified October 15 17:24 EDT 2019. Contains 328037 sequences. (Running on oeis4.)