A264286 Number of (2+1)X(n+1) arrays of permutations of 0..n*3+2 with each element having directed index change 0,0 0,1 1,0 or -1,-2.

1, 10, 32, 102, 360, 1228, 4156, 14148, 48188, 163956, 557884, 1898612, 6461148, 21987412, 74824380, 254631924, 866526236, 2948835860, 10035051900, 34149835828, 116213772252, 395481874772, 1345846631740, 4579990298484

Offset: 1

Author

R. H. Hardin, Nov 10 2015

Keywords

• nonn

Comments

Row 2 of A264285.

Examples

			Some solutions for n=4
..7..0..1..2..3....7..0..1..2..3....0..8..1..3..4....7..0..1..2..4
..5.13.14..8..4...12..5.14..8..4....5..6..2..7..9....5..6.14..3..9
.10..6.11.12..9...10..6.11.13..9...10.11.12.13.14...10.11.12..8.13
		

Links

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

Crossrefs

Cf. A264285.

Formula

Empirical: a(n) = a(n-1) +4*a(n-2) +10*a(n-3) +12*a(n-4) +8*a(n-5) for n>7.

Empirical g.f.: x*(1 + x)*(1 + 8*x + 10*x^2 + 10*x^3 + 8*x^4 + 4*x^5) / (1 - x - 4*x^2 - 10*x^3 - 12*x^4 - 8*x^5). - Colin Barker, Oct 28 2017