A264650 Number of (n+1)X(3+1) arrays of permutations of 0..n*4+3 with each element having directed index change 1,1 2,2 -1,0 or 0,-1.

0, 4, 4, 22, 65, 193, 628, 1905, 5929, 18406, 56934, 176612, 547378, 1696245, 5258441, 16296976, 50513593, 156566213, 485271504, 1504098056, 4661921212, 14449556758, 44786187665, 138814082217, 430252144356, 1333559942209, 4133348540461

Offset

1,2

Comments

Column 3 of A264655.

Links

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

Formula

Empirical: a(n) = 6*a(n-2) +10*a(n-3) +4*a(n-4) -2*a(n-5) -a(n-6) +4*a(n-7) +18*a(n-8) +25*a(n-9) -8*a(n-10) -6*a(n-11) -10*a(n-12) +a(n-15)

Example

Some solutions for n=4
..4..2..3..7....4..2..3..7....1..2..3..7....4..2..3..7....4..5..3..7
..5..6.10.11....8..0..1.11....5..0.10.11....5..0..1.11....8..0..1..2
.12.13..0..1...12.10..5..6...12..4.14..6...12.10.14..6...12.13.11..6
.16.14.15.19...16.14.15.19...16..8.15.19...16..8.15.19...16.14.15.10
.17.18..8..9...17.18.13..9...17.18.13..9...17.18.13..9...17.18.19..9

Crossrefs

Cf. A264655.

Sequence in context: A205142 A072696 A075219 * A272450 A271892 A271538

Adjacent sequences: A264647 A264648 A264649 * A264651 A264652 A264653

Keyword

nonn

Author

R. H. Hardin, Nov 20 2015

Status

approved