A263593 Number of length n arrays of permutations of 0..n-1 with each element moved by -4 to 4 places and the median of every three consecutive elements nondecreasing.

1, 2, 6, 16, 52, 164, 476, 1428, 4308, 12816, 38324, 114924, 343696, 1028096, 3077672, 9209704, 27556452, 82465380, 246779888, 738461796, 2209820148, 6612853424, 19788642456, 59216642832, 177203814880, 530275470412, 1586827690308

Offset

1,2

Comments

Column 4 of A263597.

Links

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

Formula

Empirical: a(n) = a(n-1) +a(n-2) +12*a(n-3) +5*a(n-4) +7*a(n-5) +2*a(n-6) +17*a(n-7) +31*a(n-8) -9*a(n-9) -14*a(n-10) +10*a(n-11) -22*a(n-12) -4*a(n-13) -4*a(n-15)

Example

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

Crossrefs

Cf. A263597.

Sequence in context: A214983 A367389 A214833 * A003446 A300668 A263594

Adjacent sequences: A263590 A263591 A263592 * A263594 A263595 A263596

Keyword

nonn

Author

R. H. Hardin, Oct 22 2015

Status

approved