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A195003
Number of lower triangles of a 7 X 7 0..n array with each element differing from all of its horizontal and vertical neighbors by one.
1
2, 69632, 641376, 2059822, 3816148, 5740166, 7686580, 9643120, 11600228, 13557614, 15515004, 17472396, 19429788, 21387180, 23344572, 25301964, 27259356, 29216748, 31174140, 33131532, 35088924, 37046316, 39003708, 40961100, 42918492
OFFSET
1,1
COMMENTS
Row 7 of A194998.
LINKS
FORMULA
Empirical: a(n) = 1957392*n - 6016308 for n>10.
Empirical g.f.: 2*x*(1 + 34814*x + 251057*x^2 + 423351*x^3 + 168940*x^4 + 83846*x^5 + 11198*x^6 + 5063*x^7 + 284*x^8 + 139*x^9 + 2*x^10 + x^11) / (1 - x)^2. - Colin Barker, May 06 2018
EXAMPLE
Some solutions for n=4:
..0..............0..............0..............0..............0
..1.0............1.0............1.0............1.0............1.0
..2.1.2..........0.1.2..........0.1.2..........2.1.2..........2.1.2
..1.2.1.2........1.0.1.2........1.2.1.2........1.2.3.4........1.0.1.2
..2.3.2.1.2......0.1.0.1.2......2.3.2.1.2......2.3.4.3.2......2.1.2.1.2
..1.2.1.2.1.2....1.0.1.0.1.2....1.2.3.2.1.0....1.2.3.2.1.0....1.2.1.0.1.2
..0.1.2.3.2.1.0..2.1.2.1.2.3.2..2.3.2.1.2.1.0..2.3.2.1.0.1.0..2.3.2.1.2.3.2
CROSSREFS
Cf. A194998.
Sequence in context: A100266 A272137 A272248 * A071067 A321246 A371645
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 07 2011
STATUS
approved