A263712 Number of length n arrays of permutations of 0..n-1 with each element moved by -3 to 3 places and every four consecutive elements having its maximum within 4 of its minimum.

1, 2, 6, 24, 78, 60, 50, 52, 70, 116, 184, 292, 449, 649, 969, 1429, 2137, 3238, 4839, 7285, 10924, 16339, 24553, 36769, 55153, 82769, 124024, 186099, 279039, 418384, 627613, 940985, 1411273, 2116505, 3173705, 4759874, 7137847, 10704221, 16053112

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-3) -a(n-4) +2*a(n-5) -a(n-6) +a(n-7) for n>18.

Empirical g.f.: x*(1 + x + 4*x^2 + 17*x^3 + 53*x^4 - 24*x^5 - 31*x^6 - 63*x^7 - 8*x^8 - 82*x^9 - 28*x^11 - 3*x^12 - 6*x^13 - 2*x^14 - 19*x^15 - 8*x^16 - 9*x^17) / (1 - x - x^3 + x^4 - 2*x^5 + x^6 - x^7). - Colin Barker, Jan 02 2019

Example

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

Crossrefs

Column 3 of A263714.

Sequence in context: A147938 A147929 A147921 * A263698 A263747 A002526

Adjacent sequences: A263709 A263710 A263711 * A263713 A263714 A263715

Keyword

nonn

Author

R. H. Hardin, Oct 24 2015

Status

approved