A189587 Number of permutations of 1..n with displacements restricted to {-5,-4,-3,-1,0,2}

1, 1, 2, 4, 10, 23, 48, 94, 188, 389, 808, 1692, 3505, 7225, 14895, 30751, 63601, 131549, 272040, 562259, 1161936, 2401478, 4963797, 10260810, 21209922, 43841365, 90619265, 187308371, 387166791, 800278120, 1654186266, 3419218303, 7067543993

Offset

1,3

Links

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

Formula

Empirical: a(n) = a(n-1) +2*a(n-3) +a(n-4) +5*a(n-5) +4*a(n-6) +9*a(n-7) -2*a(n-8) +5*a(n-9) -6*a(n-10) -2*a(n-11) -3*a(n-12) -5*a(n-13) -2*a(n-14) -3*a(n-15) -a(n-16) +a(n-19) +a(n-20) +a(n-21)

Example

Some solutions for n=11
..1....2....1....1....1....2....5....2....2....2....4....5....4....1....2....4
..2....3....3....6....2....5....3....6....3....3....3....3....3....2....3....5
..4....1....6....3....3....1....1....1....1....1....1....1....1....3....1....1
..5....5....2....2....4....4....2....4....4....8....2....2....2....4....4....2
..3....6....5....5....5....3....6....3...10....5...10....6....5....5....5....3
..6....4....4....4....6....6....4....7....9....4...11....4....9...11....9....7
..7....7...11...11....7....7...10....5....5...11....5....8....7....7...10....8
..8....9....8....8....8....8....9....9....6....6....6...11....6....6....6....6
.10...10....7....7....9...10....7...10....7....7....7....7...10...10....7...10
.11....8...10...10...10...11....8....8....8...10....8...10....8....8....8...11
..9...11....9....9...11....9...11...11...11....9....9....9...11....9...11....9

Crossrefs

Sequence in context: A173185 A294680 A189890 * A345195 A018111 A189594

Adjacent sequences: A189584 A189585 A189586 * A189588 A189589 A189590

Keyword

nonn

Author

R. H. Hardin Apr 24 2011

Status

approved