A264359 Number of (n+1)X(3+1) arrays of permutations of 0..n*4+3 with each element having directed index change 0,0 0,2 1,0 or -1,-2.

9, 36, 169, 784, 3600, 16641, 76729, 354025, 1633284, 7535025, 34762816, 160376896, 739894401, 3413480625, 15747991081, 72652889764, 335181944601, 1546351938576, 7134048689296, 32912721515521, 151841862142569, 700517916355401

Offset: 1

Author

R. H. Hardin, Nov 12 2015

Keywords

• nonn

Comments

Column 3 of A264364.

Examples

			Some solutions for n=4
..6..7..0..1....0..7..2..3....0..1..2..3....6..7..0..1....0..1..2..3
.10..5..2..3....4..1..6..5...10.11..4..7...10..5..2..3...10..5..6..7
..4.15..8..9....8..9.10.11....8..5..6..9....4..9..8.11....4.15..8..9
.18.19.12.11...18.19.12.13...18.19.12.13...18.19.14.15...18.13.12.11
.16.13.14.17...16.17.14.15...16.17.14.15...12.13.16.17...16.17.14.19
		

Links

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

Crossrefs

Cf. A264364.

Formula

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

Empirical G.f.: -x*(-9-9*x+2*x^2+2*x^3-2*x^4+x^5) / ( (x^3 -x^2 -2*x-1) *(x^3-2*x^2+5*x-1) ). - R. J. Mathar, Dec 09 2015