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A269272
Number of n X 4 0..3 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling three exactly once.
1
108, 13896, 1104264, 74853576, 4684312584, 279339197256, 16128206816904, 909870855444936, 50443519266217224, 2758864964165996616, 149253876730080113544, 8002845140585293252296, 425920265748436386105864
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 98*a(n-1) - 2401*a(n-2) for n > 3.
Conjectures from Colin Barker, Jan 20 2019: (Start)
G.f.: 36*x*(3 + 92*x + 49*x^2) / (1 - 49*x)^2.
a(n) = 72 * 49^(n-2) * (120*n-47) for n>1.
(End)
EXAMPLE
Some solutions for n=2:
3 2 2 0 1 1 0 0 3 0 2 3 0 2 0 3 2 2 3 2
2 2 3 2 1 3 2 0 2 0 1 0 2 2 2 3 0 2 3 0
CROSSREFS
Column 4 of A269276.
Sequence in context: A269093 A113853 A209043 * A209015 A299951 A230273
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 21 2016
STATUS
approved