A184035 1/16 the number of (n+1) X 6 0..3 arrays with all 2 X 2 subblocks having the same four values.

169, 181, 202, 244, 322, 478, 778, 1378, 2554, 4906, 9562, 18874, 37402, 74458, 148378, 296218, 591514, 1182106, 2362522, 4723354, 9443482, 18883738, 37761178, 75516058, 151019674, 302026906, 604029082, 1208033434, 2416017562, 4831985818

Offset

1,1

Comments

Column 5 of A184039.

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).

Conjectures from Colin Barker, Apr 10 2018: (Start)

G.f.: x*(169 - 326*x - 341*x^2 + 652*x^3) / ((1 - x)*(1 - 2*x)*(1 - 2*x^2)).

a(n) = 9*2^(n/2-1) + 9*2^(n-1) + 154 for n even.

a(n) = 9*2^(n-1) + 3*2^((n+1)/2) + 154 for n odd.

(End)

Example

Some solutions for 3 X 6:
..1..2..0..3..0..2....0..0..3..1..3..1....3..2..2..2..3..2....0..0..2..0..0..3
..0..3..1..2..1..3....3..1..0..0..0..0....2..2..3..2..2..2....2..3..0..3..2..0
..1..2..0..3..0..2....0..0..3..1..3..1....3..2..2..2..3..2....0..0..2..0..0..3

Crossrefs

Cf. A184039.

Sequence in context: A003929 A343269 A240069 * A044869 A260055 A235718

Adjacent sequences: A184032 A184033 A184034 * A184036 A184037 A184038

Keyword

nonn

Author

R. H. Hardin, Jan 08 2011

Status

approved