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A195001
Number of lower triangles of a 5 X 5 0..n array with each element differing from all of its horizontal and vertical neighbors by one.
1
2, 576, 2290, 4990, 7858, 10804, 13754, 16706, 19658, 22610, 25562, 28514, 31466, 34418, 37370, 40322, 43274, 46226, 49178, 52130, 55082, 58034, 60986, 63938, 66890, 69842, 72794, 75746, 78698, 81650, 84602, 87554, 90506, 93458, 96410, 99362
OFFSET
1,1
COMMENTS
Row 5 of A194998.
LINKS
FORMULA
Empirical: a(n) = 2952*n - 6910 for n>6.
Empirical g.f.: 2*x*(1 + 286*x + 570*x^2 + 493*x^3 + 84*x^4 + 39*x^5 + 2*x^6 + x^7) / (1 - x)^2. - Colin Barker, May 06 2018
EXAMPLE
Some solutions for n=4:
..0..........0..........1..........0..........0..........4..........1
..1.2........1.2........2.1........1.2........1.0........3.2........2.1
..2.1.0......2.1.2......1.2.3......2.1.2......2.1.0......2.3.2......1.2.3
..1.2.1.2....1.2.1.2....0.1.2.3....3.2.3.4....3.2.1.2....3.4.3.2....0.1.2.3
..0.1.2.3.4..2.1.0.1.0..1.2.3.2.3..2.3.2.3.2..2.3.2.1.0..4.3.2.1.0..1.2.3.4.3
CROSSREFS
Cf. A194998.
Sequence in context: A049364 A380742 A159529 * A163277 A003830 A134371
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 07 2011
STATUS
approved