A264091 Number of (2+1) X (n+1) arrays of permutations of 0..n*3+2 with each element having index change +-(.,.) 0,0 0,1 or 2,-2.

8, 39, 245, 1448, 8788, 52941, 319906, 1931215, 11662916, 70424784, 425271833, 2568026357, 15507276040, 93641933931, 565464943933, 3414607784344, 20619400388756, 124512001036665, 751876313098274, 4540269056516843

Offset

1,1

Links

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

Formula

Empirical: a(n) = 4*a(n-1) + 16*a(n-2) - 16*a(n-3) - 41*a(n-4) + 16*a(n-5) + 16*a(n-6) - 4*a(n-7) - a(n-8).

Empirical g.f.: x*(8 + 7*x - 39*x^2 - 28*x^3 + 28*x^4 + 12*x^5 - 5*x^6 - x^7) / ((1 + x - x^2)*(1 - x - x^2)*(1 - 4*x - 13*x^2 + 4*x^3 + x^4)). - Colin Barker, Jan 04 2019

Example

Some solutions for n=4:
..1..0..2..4..3....0..1.10..2..3....1..0..2..3..4....0..2..1..3..4
..6..5..8..7..9....6..5..7..9..8....6..5..7..8..9....6..5..7..9..8
.11.10.13.12.14...11.12..4.14.13...11.10.12.13.14...10.11.12.13.14

Crossrefs

Row 2 of A264090.

Sequence in context: A215731 A144414 A045909 * A353211 A319362 A154425

Adjacent sequences: A264088 A264089 A264090 * A264092 A264093 A264094

Keyword

nonn

Author

R. H. Hardin, Nov 03 2015

Status

approved