A209538 Number of nX3 array permutations with every element making zero or one right-handed knight moves (out 2, right 1)

1, 2, 16, 72, 243, 1125, 5000, 20480, 86528, 371293, 1565109, 6612354, 28063056, 118894600, 503284375, 2132531225, 9034882704, 38268370944, 162106085376, 686719856393, 2908947562937, 12322398111010, 52198820570000

Offset

1,2

Comments

Column 3 of A209543

Links

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

Formula

Empirical: a(n) = 4*a(n-1) +a(n-2) -72*a(n-5) +288*a(n-6) +72*a(n-7) +306*a(n-10) -1224*a(n-11) -306*a(n-12) +72*a(n-15) -288*a(n-16) -72*a(n-17) -a(n-20) +4*a(n-21) +a(n-22)

Example

Some solutions for n=4
..0..1..7....0..1..7....0..1..2....0..1..2....0..1..7....0..6..7....5..6..2
..8..4..5....3..4.10....8..4.10....3..9.10....8..9..5....3..4.10....8..4..0
.11..2..3...11..2..8...11..7..3...11..7..8...11..2..3....1..2..8....1..7..3
..9.10..6....9..5..6....9..5..6....4..5..6....4.10..6....9..5.11....9.10.11

Crossrefs

Sequence in context: A006733 A034580 A359519 * A006729 A007758 A207874

Adjacent sequences: A209535 A209536 A209537 * A209539 A209540 A209541

Keyword

nonn

Author

R. H. Hardin Mar 10 2012

Status

approved