A222867 Number of n X 1 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.

1, 2, 3, 7, 20, 67, 254, 1057, 4700, 21847, 104474, 508477, 2501480, 12386227, 61570694, 306778297, 1530678260, 7643776207, 38190084914, 190864134517, 954061999040, 4769534367787, 23845345743134, 119219752001137

Offset

1,2

Comments

Column 1 of A222871.

Links

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

Formula

Empirical: a(n) = 11*a(n-1) - 41*a(n-2) + 61*a(n-3) - 30*a(n-4) for n>6.

Empirical g.f.: x*(1 + x)*(1 - 10*x + 32*x^2 - 37*x^3 + 11*x^4) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 5*x)). - Colin Barker, Aug 16 2018

Example

All solutions for n=3:
..0....0....0
..1....1....0
..2....1....1

Crossrefs

Cf. A222871.

Sequence in context: A052402 A300041 A222939 * A222776 A222890 A011968

Adjacent sequences: A222864 A222865 A222866 * A222868 A222869 A222870

Keyword

nonn

Author

R. H. Hardin, Mar 07 2013

Status

approved