A208635 Number of n X 6 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than one of its immediate leftward or upward or right-upward antidiagonal neighbors.

32, 95, 309, 1042, 3577, 12404, 43284, 151656, 532795, 1875161, 6607478, 23301225, 82215220, 290187784, 1024490960, 3617470935, 12774594765, 45114821146, 159335044937, 562751474084, 1987608261228, 7020221345560, 24795605196403

Offset

1,1

Comments

Column 6 of A208637.

Links

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

Formula

Empirical: a(n) = 7*a(n-1) - 15*a(n-2) + 10*a(n-3) - a(n-4).

Empirical g.f.: x*(32 - 129*x + 124*x^2 - 16*x^3) / ((1 - x)*(1 - 6*x + 9*x^2 - x^3)). - Colin Barker, Jul 05 2018

Example

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

Crossrefs

Cf. A208637.

Sequence in context: A124804 A188184 A126386 * A259715 A195088 A050429

Adjacent sequences: A208632 A208633 A208634 * A208636 A208637 A208638

Keyword

nonn

Author

R. H. Hardin, Feb 29 2012

Status

approved