A206233 Number of (n+1) X 4 0..3 arrays with every 2 X 3 or 3 X 2 subblock having exactly two equal edges, and new values 0..3 introduced in row major order.

310, 1136, 4456, 27168, 133392, 607008, 3503136, 17206032, 78302496, 451903008, 2219576592, 10101020448, 58295486496, 286325378832, 1303031636256, 7520117756448, 36935973867792, 168091081075488, 970095190580256

Offset

1,1

Comments

Column 3 of A206238.

Links

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

Formula

Empirical: a(n) = a(n-1) + 129*a(n-3) - 129*a(n-4) for n>7.

Empirical g.f.: 2*x*(155 + 413*x + 1660*x^2 - 8639*x^3 - 165*x^4 + 22668*x^5 - 16860*x^6) / ((1 - x)*(1 - 129*x^3)). - Colin Barker, Jun 14 2018

Example

Some solutions for n=4:
..0..1..2..0....0..0..1..0....0..0..1..0....0..0..1..1....0..0..1..0
..3..2..2..0....0..1..0..0....2..0..0..2....1..1..0..1....2..0..0..1
..2..2..1..2....1..0..0..1....3..1..0..0....2..1..1..0....3..1..0..0
..2..1..2..2....0..0..2..3....3..3..1..0....1..2..1..1....3..3..1..0
..3..2..2..3....1..1..3..3....1..3..3..1....1..1..0..0....0..3..3..1

Crossrefs

Cf. A206238.

Sequence in context: A051981 A134549 A304384 * A254972 A237697 A218103

Adjacent sequences: A206230 A206231 A206232 * A206234 A206235 A206236

Keyword

nonn

Author

R. H. Hardin, Feb 05 2012

Status

approved