A222942 Number of n X 4 0..4 arrays with no element equal to another at a city block distance of exactly two, and new values 0..4 introduced in row major order.

7, 273, 5880, 130680, 2883000, 63772920, 1409319480, 31155452280, 688658403000, 15222762787320, 336492918625080, 7438082253365880, 164416380693123000, 3634373283904809720, 80336675486923162680, 1775817062973868911480

Offset

1,1

Comments

Column 4 of A222944.

Links

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

Formula

Empirical: a(n) = 17*a(n-1) + 136*a(n-2) -512*a(n-3) for n>5.

Empirical g.f.: x*(7 + 154*x + 287*x^2 - 2824*x^3 + 1536*x^4) / ((1 + 8*x)*(1 - 25*x + 64*x^2)). - Colin Barker, Aug 16 2018

Example

Some solutions for n=3:
..0..1..2..3....0..1..2..3....0..1..1..0....0..1..2..0....0..1..2..3
..2..1..4..3....3..4..2..0....2..3..3..0....3..1..4..3....4..1..2..4
..2..0..0..2....2..0..3..1....1..0..2..4....3..2..0..1....4..0..0..4

Crossrefs

Cf. A222944.

Sequence in context: A140031 A066413 A332127 * A289634 A065581 A062646

Adjacent sequences: A222939 A222940 A222941 * A222943 A222944 A222945

Keyword

nonn

Author

R. H. Hardin, Mar 09 2013

Status

approved