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A280806
Number of nX4 0..1 arrays with no element equal to more than two of its horizontal, vertical and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.
1
0, 18, 332, 2146, 9715, 37644, 133067, 440282, 1387898, 4213683, 12419791, 35750871, 100948088, 280549719, 769389206, 2086323089, 5602827011, 14920267585, 39440232733, 103577644060, 270436207834, 702418367935
OFFSET
1,2
COMMENTS
Column 4 of A280810.
LINKS
FORMULA
Empirical: a(n) = 10*a(n-1) -39*a(n-2) +72*a(n-3) -57*a(n-4) +12*a(n-5) -31*a(n-6) +61*a(n-7) +39*a(n-8) -148*a(n-9) +58*a(n-10) +72*a(n-11) +2*a(n-12) -92*a(n-13) -33*a(n-14) +142*a(n-15) -25*a(n-16) -90*a(n-17) +22*a(n-18) +50*a(n-19) +3*a(n-20) -47*a(n-21) +5*a(n-22) +30*a(n-23) -12*a(n-24) -9*a(n-25) +6*a(n-26) +a(n-27) -a(n-28) for n>36
EXAMPLE
Some solutions for n=4
..0..0..1..0. .0..1..0..0. .0..1..0..1. .0..0..1..0. .0..0..0..0
..0..1..0..1. .1..0..1..1. .0..1..0..1. .1..0..0..1. .1..1..1..1
..0..1..0..0. .0..0..0..0. .1..1..0..0. .0..1..1..1. .0..0..1..0
..1..0..1..1. .1..1..1..1. .0..0..1..1. .1..0..0..0. .1..0..0..0
CROSSREFS
Cf. A280810.
Sequence in context: A041614 A222812 A166787 * A068771 A039646 A212669
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 08 2017
STATUS
approved