A232591 Number of (2+1) X (n+1) 0..2 arrays with every element next to itself plus and minus one within the range 0..2 horizontally or antidiagonally, with no adjacent elements equal.

2, 34, 12, 152, 108, 690, 744, 3232, 4516, 15592, 25724, 76914, 141516, 385622, 762648, 1955944, 4058152, 10001440, 21421592, 51425362, 112496648, 265415854, 588810972, 1373336224, 3075128652, 7118096080, 16037159652, 36935382354

Offset

1,1

Links

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

Formula

Empirical: a(n) = 5*a(n-2) + 4*a(n-3) - 3*a(n-4) - 12*a(n-5) - 3*a(n-6) + 6*a(n-7) + 6*a(n-8) + 2*a(n-9) for n>10.

Empirical g.f.: x*(1 + 17*x + x^2 - 13*x^3 - 41*x^4 + 4*x^5 + 23*x^6 + 20*x^7 + 2*x^8 - x^9) / (1 - 5*x^2 - 4*x^3 + 3*x^4 + 12*x^5 + 3*x^6 - 6*x^7 - 6*x^8 - 2*x^9). - Colin Barker, Oct 05 2018

Example

Some solutions for n=7:
..2..1..0..2..1..0..1..0....0..1..2..0..1..0..1..2....2..1..0..1..2..0..1..2
..2..1..0..2..1..2..1..0....2..0..1..2..1..2..1..0....2..1..2..1..2..0..1..2
..0..2..1..0..1..2..1..2....1..2..1..0..1..0..1..2....0..1..0..1..2..0..1..2

Crossrefs

Row 2 of A232589.

Sequence in context: A109336 A180342 A343905 * A098869 A131544 A123284

Adjacent sequences: A232588 A232589 A232590 * A232592 A232593 A232594

Keyword

nonn

Author

R. H. Hardin, Nov 26 2013

Status

approved