A222868 Number of n X 2 0..5 arrays with no element equal to another at a city block distance of exactly two, and new values 0..5 introduced in row major order.

2, 7, 34, 370, 5314, 82690, 1313794, 20983810, 335593474, 5368905730, 85900132354, 1374392680450, 21990245138434, 351843771219970, 5629499735539714, 90071993352716290, 1441151883979784194, 23058430105021841410

Offset

1,1

Comments

Column 2 of A222871.

Links

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

Formula

Empirical: a(n) = 21*a(n-1) - 84*a(n-2) + 64*a(n-3) for n>5.

Empirical g.f.: x*(2 - 35*x + 55*x^2 + 116*x^3 - 48*x^4) / ((1 - x)*(1 - 4*x)*(1 - 16*x)). - Colin Barker, Aug 16 2018

Example

Some solutions for n=3:
..0..0....0..1....0..0....0..0....0..1....0..1....0..1....0..1....0..1....0..1
..1..2....2..2....1..2....1..2....2..3....0..2....0..2....2..1....2..3....2..3
..1..3....1..3....3..4....1..2....1..0....3..4....3..3....3..3....4..5....4..4

Crossrefs

Cf. A222871.

Sequence in context: A110313 A000944 A136310 * A222777 A222891 A342411

Adjacent sequences: A222865 A222866 A222867 * A222869 A222870 A222871

Keyword

nonn

Author

R. H. Hardin, Mar 07 2013

Status

approved