A264342 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 1,2.

8, 55, 490, 3567, 28925, 223356, 1759250, 13750304, 107777857, 843913133, 6610346674, 51772001513, 405494413096, 3175909815583, 24874462255642, 194822212724279, 1525890963999701, 11951115491689468, 93603785927597586

Offset: 1

Author

R. H. Hardin, Nov 11 2015

Keywords

• nonn

Comments

Row 2 of A264341.

Examples

			Some solutions for n=4
..0..8..9..4..3....0..2..1..4..3....0..8..1..4..3....0..8..3..2..4
..6..5.14..1..2....6..5.14..9..8....6..5.14..9..2....6..5..7..1..9
.10.11.13.12..7...10.11.13.12..7...10.12.11.13..7...10.11.13.12.14
		

Links

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

Crossrefs

Cf. A264341.

Formula

Empirical: a(n) = 6*a(n-1) +26*a(n-2) -72*a(n-3) -195*a(n-4) +284*a(n-5) +555*a(n-6) -424*a(n-7) -555*a(n-8) +284*a(n-9) +195*a(n-10) -72*a(n-11) -26*a(n-12) +6*a(n-13) +a(n-14)