A189437 Number of 5 X n array permutations with each element not moving, or moving one space N, SW or SE.

1, 20, 109, 841, 5680, 40065, 278105, 1940868, 13518605, 94223329, 656569824, 4575509121, 31884910129, 222195588532, 1548403370477, 10790295445561, 75193858910224, 524000231073025, 3651577819301001, 25446593414689700

Offset

1,2

Comments

Row 5 of A189435.

Links

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

Formula

Empirical: a(n) = 10*a(n-1) -17*a(n-2) -47*a(n-3) +138*a(n-4) -75*a(n-5).

Empirical g.f.: x*(1 - x)*(1 + 11*x - 63*x^2 + 75*x^3) / (1 - 10*x + 17*x^2 + 47*x^3 - 138*x^4 + 75*x^5). - Colin Barker, May 02 2018

Example

Some solutions for 5 X 3:
..0..4..5....3..4..2....3..1..2....0..1..2....0..4..5....3..4..2....3..4..2
..6..2..1....1..0..5....6..0..8....3..4..8....6..2..1....1..0..8....1..0..8
..9..3..8....6..7.11....4..5.11....6..5.11....9..3.11....6..5.11....6..5.11
..7.13.14....9..8.14....9.10..7...12.13..7...12..8..7...12.13..7....7.13.14
.12.11.10...12.13.10...12.13.14...10..9.14...10.13.14...10..9.14...12..9.10

Crossrefs

Cf. A189435.

Sequence in context: A173963 A202957 A232586 * A285698 A109854 A008383

Adjacent sequences: A189434 A189435 A189436 * A189438 A189439 A189440

Keyword

nonn

Author

R. H. Hardin, Apr 22 2011

Status

approved