A264300 Number of (1+1) X (n+1) arrays of permutations of 0..n*2+1 with each element having directed index change 0,1 0,-2 1,0 or -1,0.

1, 2, 5, 10, 16, 29, 61, 117, 212, 401, 776, 1476, 2777, 5261, 10025, 19042, 36065, 68410, 129940, 246641, 467857, 887753, 1685008, 3197825, 6067984, 11514880, 21852673, 41470425, 78696985, 149342234, 283409213, 537827666, 1020631824

Offset

1,2

Links

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

Formula

Empirical: a(n) = a(n-1) + 3*a(n-3) + a(n-4) + a(n-5) - 3*a(n-6) - 2*a(n-7) + a(n-9).

Empirical g.f.: x*(1 + x + 3*x^2 + 2*x^3 - x^4 - 5*x^5 - 2*x^6 + x^7 + x^8) / (1 - x - 3*x^3 - x^4 - x^5 + 3*x^6 + 2*x^7 - x^9). - Colin Barker, Jan 07 2019

Example

Some solutions for n=4:
..5..0..1..2..9....5..6..1..2..3....5..6..7..8..9....5..0..4..2..9
..7..8..6..3..4....0..8..9..7..4....0..1..2..3..4....7..1..6..3..8

Crossrefs

Row 1 of A264299.

Sequence in context: A027613 A192701 A258601 * A326763 A067112 A101306

Adjacent sequences: A264297 A264298 A264299 * A264301 A264302 A264303

Keyword

nonn

Author

R. H. Hardin, Nov 11 2015

Status

approved