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A184037
1/16 the number of (n+1) X 8 0..3 arrays with all 2 X 2 subblocks having the same four values.
2
625, 637, 658, 700, 778, 934, 1234, 1834, 3010, 5362, 10018, 19330, 37858, 74914, 148834, 296674, 591970, 1182562, 2362978, 4723810, 9443938, 18884194, 37761634, 75516514, 151020130, 302027362, 604029538, 1208033890, 2416018018, 4831986274
OFFSET
1,1
COMMENTS
Column 7 of A184039.
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) - 6*a(n-3) + 4*a(n-4).
Conjectures from Colin Barker, Apr 10 2018: (Start)
G.f.: x*(625 - 1238*x - 1253*x^2 + 2476*x^3) / ((1 - x)*(1 - 2*x)*(1 - 2*x^2)).
a(n) = 9*2^(n/2-1) + 9*2^(n-1) + 610 for n even.
a(n) = 9*2^(n-1) + 3*2^((n+1)/2) + 610 for n odd.
(End)
EXAMPLE
Some solutions for 3 X 8:
..2..2..2..2..2..2..2..1....0..0..3..2..0..2..0..2....2..3..2..3..1..3..2..3
..3..1..3..1..3..1..3..2....3..2..0..0..3..0..3..0....1..2..1..2..2..2..1..2
..2..2..2..2..2..2..2..1....0..0..3..2..0..2..0..2....2..3..2..3..1..3..2..3
CROSSREFS
Cf. A184039.
Sequence in context: A005081 A210115 A186484 * A186483 A043352 A223183
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 08 2011
STATUS
approved