A264536 Number of (3+1) X (n+1) arrays of permutations of 0..n*4+3 with each element having directed index change -2,-2 -1,0 0,1 or 1,0.

1, 4, 13, 29, 89, 261, 673, 1949, 5545, 15045, 42609, 119917, 331641, 931669, 2611393, 7272829, 20371529, 57014501, 159195153, 445435789, 1245975065, 3482261365, 9739722849, 27238546077, 76152655081, 212964930309, 595543665073

Offset

1,2

Links

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

Formula

Empirical: a(n) = a(n-1) + 12*a(n-3) + 16*a(n-5).

Empirical g.f.: x*(1 + 3*x + 9*x^2 + 4*x^3 + 12*x^4) / ((1 + 2*x + 4*x^2)*(1 - 3*x + 2*x^2 - 4*x^3)). - Colin Barker, Jan 08 2019

Example

Some solutions for n=4:
..5.13.14..2..9....5.13.14..2..9....5..6.14..2..3...12.13..1..2..3
..0..1..6..3..4....0..1.12..3..4....0..1.19..7..4....0.18.19..7..4
.15.16..7..8.19...15..6..7..8.19...15.16.17..8..9....5..6.11..8..9
.10.11.12.17.18...10.11.16.17.18...10.11.12.13.18...10.15.16.17.14

Crossrefs

Row 3 of A264534.

Sequence in context: A015634 A266891 A241399 * A161742 A041301 A138989

Adjacent sequences: A264533 A264534 A264535 * A264537 A264538 A264539

Keyword

nonn

Author

R. H. Hardin, Nov 17 2015

Status

approved