A198529 Number of 2nX4 0..2 arrays with values 0..2 introduced in row major order and each element equal to exactly one horizontal or vertical neighbor

12, 206, 3838, 74582, 1481214, 29737425, 600187403, 12144602583, 246046084954, 4987787543526, 101140166737445, 2051157938501522, 41600949234763960, 843764349062814286, 17113771581568185569, 347115075675201580800

Offset

1,1

Comments

Column 2 of A198532

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = 42*a(n-1) -599*a(n-2) +3637*a(n-3) -8567*a(n-4) -1138*a(n-5) +28475*a(n-6) -23674*a(n-7) -2916*a(n-8) +112776*a(n-9) -163480*a(n-10) -147783*a(n-11) -101412*a(n-12) -148912*a(n-13) +747248*a(n-14) +967680*a(n-15) -1452032*a(n-16) -4042752*a(n-17) -7405568*a(n-18) -7340032*a(n-19) -4194304*a(n-20)

Example

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

Crossrefs

Sequence in context: A108020 A097193 A051688 * A372616 A151590 A297311

Adjacent sequences: A198526 A198527 A198528 * A198530 A198531 A198532

Keyword

nonn

Author

R. H. Hardin Oct 26 2011

Status

approved