A222776 Number of n X 1 0..6 arrays with no element equal to another at a city block distance of exactly two, and new values 0..6 introduced in row major order.

1, 2, 3, 7, 20, 67, 255, 1079, 4987, 24759, 129947, 710791, 4004619, 23031191, 134328379, 790907943, 4686298091, 27884452663, 166383085851, 994632987335, 5953222496203, 35661292725975, 213736364551163, 1281494949329767

Offset

1,2

Comments

Column 1 of A222779.

Links

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

Formula

Empirical: a(n) = 16*a(n-1) - 95*a(n-2) + 260*a(n-3) - 324*a(n-4) + 144*a(n-5) for n>7.

Empirical g.f.: x*(1 + x)*(1 - 15*x + 81*x^2 - 192*x^3 + 189*x^4 - 53*x^5) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)*(1 - 6*x)). - Colin Barker, Aug 16 2018

Example

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

Crossrefs

Cf. A222779.

Sequence in context: A300041 A222939 A222867 * A222890 A011968 A080021

Adjacent sequences: A222773 A222774 A222775 * A222777 A222778 A222779

Keyword

nonn

Author

R. H. Hardin, Mar 05 2013

Status

approved