A189588 Number of permutations of 1..n with displacements restricted to {-5,-4,-3,0,1,2}.

1, 1, 1, 4, 13, 35, 73, 147, 322, 746, 1758, 4042, 9114, 20444, 46217, 105155, 239481, 544259, 1234420, 2798863, 6350149, 14416419, 32732101, 74301920, 168633936, 382715304, 868630024, 1971599952, 4475144212, 10157494573, 23054646277

Offset: 1

Author

R. H. Hardin Apr 24 2011

Keywords

• nonn

Examples

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

Links

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

Formula

Empirical: a(n) = a(n-1) +2*a(n-3) +4*a(n-4) +7*a(n-5) +11*a(n-6) +14*a(n-7) +2*a(n-9) -14*a(n-10) -6*a(n-11) -8*a(n-12) -10*a(n-13) -10*a(n-14) -a(n-15) -3*a(n-16) +2*a(n-17) +a(n-20) +a(n-21)