A264158 - OEIS

A264158

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

4, 10, 29, 89, 260, 772, 2281, 6741, 19940, 58954, 174329, 515481, 1524232, 4507072, 13327105, 39407393, 116525124, 344557218, 1018833429, 3012624481, 8908135596, 26340780436, 77887982793, 230309723973, 681010947204, 2013705293106

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OFFSET

1,1

COMMENTS

Column 1 of A264163.

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) + 2*a(n-2) + 2*a(n-3) + 4*a(n-5) - a(n-8).

Empirical g.f.: x*(4 + 2*x + x^2 + 3*x^3 + 4*x^4 - x^6 - x^7) / (1 - 2*x - 2*x^2 - 2*x^3 - 4*x^5 + x^8). - Colin Barker, Mar 21 2018

EXAMPLE

Some solutions for n=4:

..1..0....1..0....1..3....2..3....2..3....1..0....2..0....2..0....1..0....1..3

..4..5....3..2....0..2....0..1....0..1....3..2....3..5....4..1....4..5....0..5

..2..3....5..7....5..7....5..7....6..7....5..4....6..1....6..3....2..3....6..7

..7..9....4..6....4..9....4..9....4..5....8..9....8..9....8..5....8..9....2..9

..6..8....9..8....6..8....6..8....9..8....6..7....4..7....9..7....6..7....4..8

CROSSREFS

Cf. A264163.

Sequence in context: A221420 A212262 A233347 * A152808 A243601 A243602

Adjacent sequences: A264155 A264156 A264157 * A264159 A264160 A264161

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 06 2015

STATUS

approved