A263678 Number of length n arrays of permutations of 0..n-1 with each element moved by -3 to 3 places and with no two consecutive decreases.

1, 2, 5, 17, 53, 155, 429, 1210, 3457, 9948, 28528, 81636, 233344, 667390, 1909626, 5464861, 15637212, 44741387, 128011961, 366269502, 1047988385, 2998562936, 8579622673, 24548350663, 70238679485, 200969734254, 575022887468

Offset

1,2

Comments

Column 3 of A263683.

Links

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

Formula

Empirical: a(n) = a(n-1) +3*a(n-2) +3*a(n-3) +5*a(n-4) +9*a(n-5) +22*a(n-6) -21*a(n-8) -13*a(n-9) +2*a(n-10) +3*a(n-11) -15*a(n-12) +7*a(n-14) +5*a(n-15) -a(n-16) -2*a(n-17) +3*a(n-18) -a(n-20).

Example

Some solutions for n=7
..1....0....2....0....0....0....1....0....0....2....0....2....1....1....3....0
..0....4....0....1....2....1....3....2....2....0....1....1....4....3....1....1
..5....5....1....3....3....2....0....1....1....4....5....4....0....4....5....3
..2....6....5....2....1....6....2....3....6....1....2....0....2....0....0....2
..3....1....3....5....4....3....4....5....3....6....6....3....3....2....6....4
..6....2....6....4....5....4....5....4....4....3....3....6....5....5....2....6
..4....3....4....6....6....5....6....6....5....5....4....5....6....6....4....5

Crossrefs

Cf. A263683.

Sequence in context: A148406 A148407 A141303 * A133510 A191640 A148408

Adjacent sequences: A263675 A263676 A263677 * A263679 A263680 A263681

Keyword

nonn

Author

R. H. Hardin, Oct 23 2015

Status

approved