A194780 Number of lower triangles of a (2n)X(2n) 0..n array with new values introduced in row major order 0..n and no element unequal to more than one horizontal or vertical neighbor

3, 17, 105, 672, 4490, 31466, 231445, 1784788, 14404218, 121421075, 1066906979, 9753108510, 92586250999, 911156724048

Offset

1,1

Comments

Row 2 of A194778

Links

Table of n, a(n) for n=1..14.

Example

All solutions for n=2 containing a 2
..0........0........0........0........0
..0.0......1.1......1.1......0.1......1.1
..1.1.1....1.1.1....1.1.2....0.1.1....1.1.1
..1.1.1.2..1.1.1.2..1.1.2.2..0.1.1.2..2.2.2.2

Crossrefs

Sequence in context: A264963 A036551 A162479 * A074563 A077145 A299039

Adjacent sequences: A194777 A194778 A194779 * A194781 A194782 A194783

Keyword

nonn

Author

R. H. Hardin Sep 02 2011

Status

approved