A189595 Number of permutations of 1..n with displacements restricted to {-6,-5,-4,-3,0,1,2}

1, 1, 1, 4, 13, 35, 89, 192, 418, 971, 2336, 5654, 13472, 31741, 74468, 175022, 413210, 977502, 2311729, 5460828, 12889416, 30420888, 71817384, 169592184, 400517287, 945825180, 2233383719, 5273484497, 12451877435, 29402388773, 69428451013

Offset

1,4

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = a(n-1) +2*a(n-3) +5*a(n-4) +8*a(n-5) +14*a(n-6) +23*a(n-7) +23*a(n-8) -2*a(n-9) -2*a(n-10) -41*a(n-11) -32*a(n-12) -19*a(n-13) -18*a(n-14) -15*a(n-15) -13*a(n-16) -a(n-17) -5*a(n-18) +13*a(n-19) +11*a(n-20) +3*a(n-21) +3*a(n-22) +2*a(n-23) +a(n-24) +a(n-26) -a(n-27) -a(n-28)

Example

Some solutions for n=10
..5....1....5....4....4....5....6....1....5....1....7....1....1....1....4....1
..1....6....2....8....1....1....1....8....2....8....2....5....2....2....5....5
..2....2....1....1....7....6....2....3....1....9....1....2....3....7....1....2
..3....4...10....2....2....2....3....2....7....2....8....4....4....3....2...10
..4....3....3....3....3....3....9....4....3....3....3....3...10....4....3....3
..9...10....4....5...10....4....4....5....4....4....4....6....5....5....6....4
..7....5....7...10....5...10....5...10...10....5....5...10....6...10...10....7
..6....8....6....6....6....7....7....6....6....6....6....8....7....6....7....6
..8....7....8....7....8....8....8....7....9....7....9....7....8....8....9....8
.10....9....9....9....9....9...10....9....8...10...10....9....9....9....8....9

Crossrefs

Sequence in context: A095941 A210843 A177155 * A189602 A317781 A271358

Adjacent sequences: A189592 A189593 A189594 * A189596 A189597 A189598

Keyword

nonn

Author

R. H. Hardin Apr 24 2011

Status

approved