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A184606 Half the number of (n+1) X 2 binary arrays with no 2 X 2 subblock sum differing from a horizontal or vertical neighbor subblock sum by more than one. 1
8, 28, 98, 350, 1250, 4450, 15842, 56426, 200978, 715786, 2549282, 9079418, 32336882, 115169482, 410182082, 1460885210, 5203020050, 18530830570, 65998531298, 235057255034, 837168828722, 2981620996234, 10619200644098 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A184614.

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) + 6*a(n-3) + 4*a(n-4).

Empirical g.f.: 2*x*(4 + 2*x + 7*x^2 + 4*x^3) / ((1 + 2*x^2)*(1 - 3*x - 2*x^2)). - Colin Barker, Apr 14 2018

EXAMPLE

Some solutions for 3 X 2:

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

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

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

...

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

...1.......2.......2.......1.......3.......1.......1.......4.......3.......3...

CROSSREFS

Cf. A184614.

Sequence in context: A333283 A211066 A095857 * A054114 A305907 A110687

Adjacent sequences: A184603 A184604 A184605 * A184607 A184608 A184609

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 18 2011

STATUS

approved

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Last modified December 3 20:52 EST 2022. Contains 358543 sequences. (Running on oeis4.)