A209781 Half the number of (n+1)X3 0..3 arrays with every 2X2 subblock having exactly one duplicate clockwise edge difference

576, 12492, 266126, 5719838, 122871278, 2641341716, 56780957220, 1220714555712, 26243950399348, 564220215862026, 12130228710486118, 260789425643620742, 5606749493903244274, 120540344808285189504, 2591515087636992673274

Offset

1,1

Comments

Column 2 of A209787

Links

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

Formula

Empirical: a(n) = 32*a(n-1) -181*a(n-2) -1612*a(n-3) +14245*a(n-4) +3934*a(n-5) -228072*a(n-6) +286957*a(n-7) +1135539*a(n-8) -2087315*a(n-9) -2118396*a(n-10) +5249880*a(n-11) +1194011*a(n-12) -5705343*a(n-13) +530140*a(n-14) +2648017*a(n-15) -619565*a(n-16) -439672*a(n-17) +116050*a(n-18) +17928*a(n-19) -3952*a(n-20)

Example

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

Crossrefs

Sequence in context: A235738 A236078 A264524 * A330840 A226285 A370226

Adjacent sequences: A209778 A209779 A209780 * A209782 A209783 A209784

Keyword

nonn

Author

R. H. Hardin Mar 13 2012

Status

approved