A264584 Number of (1+1) X (n+1) arrays of permutations of 0..n*2+1 with each element having directed index change 1,0 0,-1 1,2 or -1,1.

0, 1, 0, 1, 1, 1, 3, 1, 3, 6, 5, 9, 10, 15, 24, 25, 39, 55, 70, 101, 130, 184, 256, 332, 467, 636, 862, 1186, 1596, 2201, 3006, 4066, 5581, 7600, 10371, 14161, 19265, 26351, 35935, 48961, 66866, 91169, 124417, 169726, 231425, 315892, 430865, 587699

Offset

1,7

Links

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

Formula

Empirical: a(n) = a(n-3) + a(n-4) + 2*a(n-5) - a(n-9) - a(n-10).

Empirical g.f.: x^2*(1 - x)*(1 + x + 2*x^2 + 2*x^3 + 2*x^4 + 2*x^5 + x^6) / (1 - x^3 - x^4 - 2*x^5 + x^9 + x^10). - Colin Barker, Jan 08 2019

Example

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

Crossrefs

Row 1 of A264583.

Sequence in context: A255974 A033789 A109532 * A137338 A176106 A302867

Adjacent sequences: A264581 A264582 A264583 * A264585 A264586 A264587

Keyword

nonn

Author

R. H. Hardin, Nov 18 2015

Status

approved