A263999 Number of (n+1) X (2+1) arrays of permutations of 0..n*3+2 with each element having index change (+-,+-) 0,0 1,2 or 1,0.

18, 99, 925, 7304, 62101, 516117, 4331090, 36234055, 303517857, 2541399696, 21283031073, 178225556041, 1492505510450, 12498522497307, 104665286104629, 876488490428056, 7339896528996157, 61465808537919885, 514727394291340594

Offset

1,1

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) -44*a(n-3) -256*a(n-4) +64*a(n-5) +256*a(n-6).

Empirical g.f.: x*(3 + 4*x)*(6 - 5*x - 72*x^2 + 32*x^3 + 64*x^4) / (1 - 5*x - 37*x^2 + 44*x^3 + 256*x^4 - 64*x^5 - 256*x^6). - Colin Barker, Jan 03 2019

Example

Some solutions for n=4:
..3..1..5....5..4..3....0..1..3....0..1..5....0..1..3....0..1..5....0..1..3
..0..4..2....0..1..2....2..4..5....3..7..2....2..7..5....2..4..6....2..4..5
.11.10..8...11..7..8....6..7.11....9..4.11....6..4..8....3.10..9....9.10..8
..6..7.14...14.13..6....8.10.14....6.13..8....9.10.12....8..7.14....6..7.14
.12.13..9...12.10..9...12.13..9...12.10.14...11.13.14...12.13.11...12.13.11

Crossrefs

Column 2 of A264003.

Sequence in context: A044650 A008920 A221911 * A087638 A231144 A259231

Adjacent sequences: A263996 A263997 A263998 * A264000 A264001 A264002

Keyword

nonn

Author

R. H. Hardin, Oct 31 2015

Status

approved