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A194933
Number of lower triangles of a 4 X 4 0..n array with no element differing from any of its horizontal or vertical neighbors by more than one.
1
1024, 5873, 12474, 19379, 26316, 33255, 40194, 47133, 54072, 61011, 67950, 74889, 81828, 88767, 95706, 102645, 109584, 116523, 123462, 130401, 137340, 144279, 151218, 158157, 165096, 172035, 178974, 185913, 192852, 199791, 206730, 213669
OFFSET
1,1
COMMENTS
Row 4 of A194931.
LINKS
FORMULA
Empirical: a(n) = 6939*n - 8379 for n>4.
Empirical g.f.: x*(1024 + 3825*x + 1752*x^2 + 304*x^3 + 32*x^4 + 2*x^5) / (1 - x)^2. - Colin Barker, May 05 2018
EXAMPLE
Some solutions for n=4:
..2........0........1........1........2........2........0........2
..1.2......0.1......0.0......2.3......1.2......1.0......0.0......2.1
..2.3.4....0.1.1....1.1.1....3.3.3....1.2.2....0.0.1....1.0.1....2.2.2
..3.3.3.4..0.0.1.1..0.1.1.2..3.2.2.2..0.1.2.1..0.1.2.2..1.0.0.0..2.2.2.3
CROSSREFS
Cf. A194931.
Sequence in context: A189071 A214800 A220765 * A231944 A318112 A197711
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 05 2011
STATUS
approved