A205920 Number of (n+1)X3 0..3 arrays with the number of clockwise edge increases in every 2X2 subblock equal to one, and every 2X2 determinant nonzero

389, 2684, 15561, 104311, 625713, 4085161, 25017018, 160810946, 996539188, 6349065953, 39612347102, 251092937558, 1572662627911, 9939718849729, 62392966075506, 393685890973241, 2474347338880118, 15597690052144653

Offset

1,1

Comments

Column 2 of A205926

Links

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

Formula

Empirical: a(n) = 5*a(n-1) +37*a(n-2) -134*a(n-3) -468*a(n-4) +446*a(n-5) +3506*a(n-6) +2929*a(n-7) +764*a(n-8) -27570*a(n-9) -19322*a(n-10) -4621*a(n-11) +18764*a(n-12) +42723*a(n-13) +11896*a(n-14) -35641*a(n-15) -21691*a(n-16) +23786*a(n-17) +548*a(n-18) -9887*a(n-19) +7551*a(n-20) -3387*a(n-21) +1201*a(n-22) -314*a(n-23) +71*a(n-24) -13*a(n-25) +a(n-26)

Example

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

Crossrefs

Sequence in context: A298238 A299364 A299133 * A299891 A299058 A299819

Adjacent sequences: A205917 A205918 A205919 * A205921 A205922 A205923

Keyword

nonn

Author

R. H. Hardin Feb 01 2012

Status

approved