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A184038 1/16 the number of (n+1) X 9 0..3 arrays with all 2 X 2 subblocks having the same four values. 1
1225, 1237, 1258, 1300, 1378, 1534, 1834, 2434, 3610, 5962, 10618, 19930, 38458, 75514, 149434, 297274, 592570, 1183162, 2363578, 4724410, 9444538, 18884794, 37762234, 75517114, 151020730, 302027962, 604030138, 1208034490, 2416018618 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 8 of A184039.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..53

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*(1225 - 2438*x - 2453*x^2 + 4876*x^3) / ((1 - x)*(1 - 2*x)*(1 - 2*x^2)).

a(n) = 9*2^(n/2-1) + 9*2^(n-1) + 1210 for n even.

a(n) = 9*2^(n-1) + 3*2^((n+1)/2) + 1210 for n odd.

(End)

EXAMPLE

Some solutions for 3 X 9:

..3..0..3..1..3..0..3..1..3....0..0..3..1..3..1..0..0..0

..1..1..1..0..1..1..1..0..1....3..1..0..0..0..0..3..1..3

..3..0..3..1..3..0..3..1..3....0..0..3..1..3..1..0..0..0

CROSSREFS

Sequence in context: A014488 A229379 A229371 * A025407 A025405 A275256

Adjacent sequences:  A184035 A184036 A184037 * A184039 A184040 A184041

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 08 2011

STATUS

approved

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Last modified May 19 18:35 EDT 2022. Contains 353847 sequences. (Running on oeis4.)