A183430 One third the number of n X 2 0..3 arrays with no element equal to its row sum plus its column sum mod 4.

4, 27, 244, 2187, 19684, 177147, 1594324, 14348907, 129140164, 1162261467, 10460353204, 94143178827, 847288609444, 7625597484987, 68630377364884, 617673396283947, 5559060566555524, 50031545098999707, 450283905890997364

Offset

1,1

Comments

Column 2 of A183433.

Links

R. H. Hardin, Table of n, a(n) for n = 1..171

Formula

Empirical: a(n) = 9*a(n-1) + a(n-2) - 9*a(n-3).

Conjectures from Colin Barker, Mar 29 2018: (Start)

G.f.: x*(4 - 9*x - 3*x^2) / ((1 - x)*(1 + x)*(1 - 9*x)).

a(n) = 9^n / 3 for n even.

a(n) = (6+2*9^n) / 6 for n odd.

(End)

Example

Some solutions for 3 X 2:
..1..2....2..0....3..1....2..2....1..3....3..0....0..1....0..2....3..3....1..1
..1..2....3..0....3..0....2..2....2..2....2..0....3..1....1..3....3..0....0..1
..3..0....2..0....3..1....1..1....0..0....1..0....3..0....2..0....1..3....1..3

Crossrefs

Cf. A183433.

Sequence in context: A181146 A303559 A161120 * A212559 A265268 A121063

Adjacent sequences: A183427 A183428 A183429 * A183431 A183432 A183433

Keyword

nonn

Author

R. H. Hardin, Jan 04 2011

Status

approved