A195002 Number of lower triangles of a 6 X 6 0..n array with each element differing from all of its horizontal and vertical neighbors by one.

2, 4608, 31042, 81014, 138956, 199988, 261324, 322806, 384292, 445780, 507268, 568756, 630244, 691732, 753220, 814708, 876196, 937684, 999172, 1060660, 1122148, 1183636, 1245124, 1306612, 1368100, 1429588, 1491076, 1552564, 1614052, 1675540

Offset

1,1

Comments

Row 6 of A194998.

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = 61488*n - 169100 for n>8.

Empirical g.f.: 2*x*(1 + 2302*x + 10914*x^2 + 11769*x^3 + 3985*x^4 + 1545*x^5 + 152*x^6 + 73*x^7 + 2*x^8 + x^9) / (1 - x)^2. - Colin Barker, May 06 2018

Example

Some solutions for n=4:
..4............2............2............4............2............0
..3.4..........3.2..........1.0..........3.4..........3.4..........1.2
..2.3.2........4.3.2........0.1.0........2.3.4........4.3.2........2.3.4
..1.2.3.2......3.2.3.4......1.2.1.2......3.4.3.4......3.4.3.2......1.2.3.2
..0.1.2.3.2....2.3.4.3.2....0.1.0.1.2....2.3.2.3.2....2.3.2.1.2....2.1.2.1.2
..1.2.1.2.1.0..3.4.3.4.3.2..1.2.1.2.1.2..3.2.3.2.3.2..3.2.3.2.1.0..3.2.3.2.1.2

Crossrefs

Cf. A194998.

Sequence in context: A178410 A067668 A292391 * A203756 A232712 A262059

Adjacent sequences: A194999 A195000 A195001 * A195003 A195004 A195005

Keyword

nonn

Author

R. H. Hardin, Sep 07 2011

Status

approved