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A251252 Number of (n+1) X (2+1) 0..1 arrays with every 2 X 2 subblock having a single 1 or two 1s on the same edge. 1
18, 56, 150, 446, 1232, 3602, 10108, 29272, 82854, 238640, 678658, 1948718, 5556204, 15926754, 45474920, 130227048, 372121034, 1065071288, 3044724350, 8711869630, 24910552504, 71264572098, 203799138404, 582977750488, 1667293062110 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) + 4*a(n-2) - 14*a(n-3) + 3*a(n-4) + 3*a(n-5).

Empirical g.f.: 2*x*(9 + x - 45*x^2 + 12*x^3 + 12*x^4) / (1 - 3*x - 4*x^2 + 14*x^3 - 3*x^4 - 3*x^5). - Colin Barker, Nov 27 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Column 2 of A251258.

Sequence in context: A086540 A041634 A044975 * A297946 A298384 A298765

Adjacent sequences: A251249 A251250 A251251 * A251253 A251254 A251255

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 01 2014

STATUS

approved

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Last modified December 4 08:59 EST 2022. Contains 358552 sequences. (Running on oeis4.)