A263692 Number of length n arrays of permutations of 0..n-1 with each element moved by -3 to 3 places and every three consecutive elements having its maximum within 3 of its minimum.

1, 2, 6, 24, 18, 18, 24, 40, 64, 100, 144, 216, 324, 496, 748, 1136, 1712, 2596, 3920, 5940, 8976, 13592, 20548, 31104, 47036, 71184, 107664, 162916, 246432, 372868, 564048, 853400, 1291012, 1953232, 2954892, 4470512, 6763184, 10232036, 15479600

Offset

1,2

Links

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

Formula

Empirical: a(n) = a(n-1) + a(n-2) - a(n-3) + a(n-4) for n>12.

Empirical g.f.: x*(1 + x + 3*x^2 + 17*x^3 - 11*x^4 - 20*x^5 + 6*x^6 - 8*x^7 + 2*x^9 - 4*x^10 - 4*x^11) / (1 - x - x^2 + x^3 - x^4). - Colin Barker, Jan 02 2019

Example

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

Crossrefs

Column 3 of A263693.

Sequence in context: A356757 A004154 A076126 * A363962 A319544 A354833

Adjacent sequences: A263689 A263690 A263691 * A263693 A263694 A263695

Keyword

nonn

Author

R. H. Hardin, Oct 23 2015

Status

approved