A233094 - OEIS

A233094

Number of n X 4 0..3 arrays with no element x(i,j) adjacent to value 3-x(i,j) horizontally, diagonally or antidiagonally, top left element zero, and 1 appearing before 2 in row major order.

14, 386, 11486, 342626, 10221326, 304926626, 9096692126, 271376130626, 8095800458126, 241517133090626, 7205034990428126, 214943464047390626, 6412278746469578126, 191293645073850390626, 5706747958483163828126

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OFFSET

1,1

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 31*a(n-1) - 35*a(n-2) + 5*a(n-3).

Conjectures from Colin Barker, Oct 07 2018: (Start)

G.f.: 2*x*(7 - 24*x + 5*x^2) / ((1 - x)*(1 - 30*x + 5*x^2)).

a(n) = (110 + (15-2*sqrt(55))^n*(55+sqrt(55)) - (-55+sqrt(55))*(15+2*sqrt(55))^n) / 110.

(End)

EXAMPLE

Some solutions for n=3:

..0..0..1..0....0..1..0..2....0..1..1..3....0..1..3..3....0..1..1..1

..2..0..0..1....3..1..0..0....3..1..3..1....3..1..1..3....1..0..0..1

..1..0..0..0....0..2..0..1....0..2..0..1....3..1..1..0....1..1..0..0

CROSSREFS

Column 4 of A233098.

Sequence in context: A171718 A270409 A000473 * A211421 A097310 A223003

Adjacent sequences: A233091 A233092 A233093 * A233095 A233096 A233097

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 04 2013

STATUS

approved