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A280808
Number of nX6 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, 284, 6540, 37644, 155560, 547197, 1736603, 5150299, 14554327, 39708623, 105469880, 274358836, 702041419, 1772651619, 4426877398, 10952897674, 26883495456, 65525790275, 158732212994, 382416259916, 916790487361
OFFSET
1,2
COMMENTS
Column 6 of A280810.
LINKS
FORMULA
Empirical: a(n) = 13*a(n-1) -72*a(n-2) +220*a(n-3) -400*a(n-4) +432*a(n-5) -256*a(n-6) +70*a(n-7) -54*a(n-8) +183*a(n-9) -249*a(n-10) -51*a(n-11) +573*a(n-12) -672*a(n-13) +249*a(n-14) +135*a(n-15) -204*a(n-16) +12*a(n-17) +225*a(n-18) -57*a(n-19) -390*a(n-20) +422*a(n-21) -107*a(n-22) -63*a(n-23) +138*a(n-24) -144*a(n-25) +33*a(n-27) +78*a(n-28) -54*a(n-29) -13*a(n-30) -17*a(n-31) -12*a(n-32) +70*a(n-33) -31*a(n-34) -12*a(n-35) +3*a(n-36) -6*a(n-37) +15*a(n-38) -3*a(n-39) -3*a(n-40) -a(n-42) +a(n-43) for n>53
EXAMPLE
Some solutions for n=4
..0..0..0..0..1..0. .0..1..0..1..1..0. .0..0..0..1..0..0. .0..0..1..1..0..1
..0..1..1..0..1..0. .0..0..1..0..1..0. .1..0..1..0..1..1. .1..1..0..0..1..0
..1..0..1..0..1..0. .1..0..0..1..0..1. .0..1..0..1..0..0. .0..0..1..1..0..0
..1..1..0..1..1..0. .1..1..0..1..0..1. .0..1..0..1..1..0. .0..1..0..0..1..1
CROSSREFS
Cf. A280810.
Sequence in context: A108110 A218400 A196893 * A285892 A049024 A277771
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 08 2017
STATUS
approved