A189584 Number of permutations of 1..n with displacements restricted to {-4,0,1,2,3}.

1, 1, 1, 1, 8, 22, 46, 85, 168, 350, 776, 1787, 3851, 8141, 17247, 36921, 79637, 172237, 371343, 797047, 1710188, 3673435, 7899653, 16995309, 36552835, 78580754, 168899252, 363064232, 780553896, 1678245531, 3608276813, 7757481797

Offset: 1

Author

R. H. Hardin Apr 24 2011

Keywords

• nonn

Examples

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

Links

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

Formula

Empirical: a(n) = a(n-1) +2*a(n-3) +2*a(n-4) +4*a(n-5) +10*a(n-6) +13*a(n-7) -3*a(n-8) +3*a(n-9) -11*a(n-10) +2*a(n-11) +5*a(n-12) -31*a(n-13) -11*a(n-14) -10*a(n-15) -3*a(n-16) +3*a(n-17) +a(n-18) -28*a(n-19) +22*a(n-20) -18*a(n-21) +10*a(n-22) -3*a(n-23) -8*a(n-24) +5*a(n-25) -4*a(n-26) -3*a(n-27) +2*a(n-28) +3*a(n-30) +2*a(n-31) -a(n-32) +a(n-33) +a(n-35)