A264191 Number of (n+1)X(2+1) arrays of permutations of 0..n*3+2 with each element having index change +-(.,.) 0,0 0,2 or 2,1.

4, 18, 81, 360, 1600, 6760, 28561, 120666, 509796, 2159850, 9150625, 38768400, 164249856, 695767824, 2947295521, 12484841330, 52886200900, 224029644930, 949005240561, 4020052555512, 17029223715904, 72136947419128

Offset

1,1

Comments

Column 2 of A264195.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) +a(n-2) -17*a(n-4) +68*a(n-5) +17*a(n-6) +17*a(n-8) -68*a(n-9) -17*a(n-10) +a(n-12) -4*a(n-13) -a(n-14)

Example

Some solutions for n=4
..2..1..0....2..1..0....0..1..2....7..8..2....0..1..2....0..8..2....7..8..2
..3..4..5....5.11..3....3.11..5....5.11..3....5..4..3....3..4..5....5..4..3
..8..7..6....6.14..8...13.14..8...13..0..1....6..7..8...13..7..1...13..0..1
.11.10..9....9.10..4....9.10..4....9.10..4...11.10..9...11.10..9...11.10..9
.12.13.14...12.13..7...12..6..7...12..6.14...12.13.14...14..6.12...12..6.14

Crossrefs

Cf. A264195.

Sequence in context: A264004 A282708 A252823 * A257060 A181610 A264927

Adjacent sequences: A264188 A264189 A264190 * A264192 A264193 A264194

Keyword

nonn

Author

R. H. Hardin, Nov 07 2015

Status

approved