A194538 Number of lower triangles of an n X n 0..6 array with new values introduced in row major order 0..6 and no element equal to more than one horizontal or vertical neighbor

1, 4, 132, 67377, 543350470, 40994098419294, 21253155706215768591, 71381360690596538575641162

Offset

1,2

Comments

Column 6 of A194540

Links

Table of n, a(n) for n=1..8.

Example

Some solutions for 3X3
..0......0......0......0......0......0......0......0......0......0......0
..0.1....1.2....1.2....1.1....1.2....1.2....1.1....1.0....0.1....1.2....1.1
..2.2.0..1.0.2..0.3.3..2.0.0..2.3.4..2.0.0..2.2.3..2.1.3..2.3.0..2.3.1..2.0.1

Crossrefs

Sequence in context: A338040 A204077 A194537 * A194539 A146547 A274703

Adjacent sequences: A194535 A194536 A194537 * A194539 A194540 A194541

Keyword

nonn

Author

R. H. Hardin Aug 28 2011

Status

approved