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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
OFFSET
1,1
COMMENTS
Column 1 of A184614.
LINKS
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
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 18 2011
STATUS
approved