A263664 Number of length n arrays of permutations of 0..n-1 with each element moved by -6 to 6 places and with no two consecutive increases or two consecutive decreases.

1, 2, 4, 10, 32, 122, 544, 2287, 7688, 25662, 79456, 256482, 809784, 2690604, 8874432, 30009480, 98599568, 332395712, 1084222064, 3637730112, 11844968640, 39726351272, 129526799072, 434837072968, 1418856843552, 4764806022144

Offset

1,2

Comments

Column 6 of A263666.

Links

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

Formula

Empirical: a(n) = 6*a(n-2) +26*a(n-4) +166*a(n-6) +1096*a(n-8) +5220*a(n-10) +2608*a(n-12) -32104*a(n-14) -26760*a(n-16) +18920*a(n-18) -246704*a(n-20) -102880*a(n-22) +272224*a(n-24) -372992*a(n-26) +1227008*a(n-28) -1025920*a(n-30) +3805952*a(n-32) -5750016*a(n-34) +3855360*a(n-36) +801280*a(n-38) -2436096*a(n-40) +253952*a(n-42) +1060864*a(n-44) -978944*a(n-46) +229376*a(n-48) +49152*a(n-50) -16384*a(n-52) for n>66

Example

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

Crossrefs

Cf. A263666.

Sequence in context: A000736 A263663 A176006 * A263665 A001250 A013032

Adjacent sequences: A263661 A263662 A263663 * A263665 A263666 A263667

Keyword

nonn

Author

R. H. Hardin, Oct 23 2015

Status

approved