A264060 Number of (2+1) X (n+1) arrays of permutations of 0..n*3+2 with each element having index change +-(.,.) 0,0 1,2 or 2,-2.

1, 8, 64, 216, 729, 3375, 15625, 64000, 262144, 1124864, 4826809, 20346417, 85766121, 363994344, 1544804416, 6539203000, 27680640625, 117289217375, 496981290961, 2105026154496, 8916100448256, 37770717892608, 160005726539569

Offset: 1

Author

R. H. Hardin, Nov 02 2015

Keywords

• nonn

Comments

Row 2 of A264059.

Examples

			Some solutions for n=4
..0..1..2.11..4....7..1..2..3..4....7..8.10.11.12....0..1.10..3..4
..5..6.14..8..9...12..6..0..8..9....5..6..0..1..9....5..6.14..8..9
.10..3.12.13..7...10.11..5.13.14....2..3..4.13.14....2.11.12.13..7
		

Links

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

Crossrefs

Cf. A264059.

Formula

Empirical: a(n) = 4*a(n-1) -4*a(n-2) +20*a(n-3) +20*a(n-4) -60*a(n-5) -60*a(n-7) -20*a(n-8) +20*a(n-9) +4*a(n-10) +4*a(n-11) +a(n-12).