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A281054
Number of nX6 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.
1
6, 251, 1403, 5400, 16875, 46610, 119205, 288527, 671451, 1515524, 3339671, 7217269, 15347530, 32196671, 66765699, 137073842, 278977066, 563443975, 1130260537, 2253558987, 4468793135, 8818038639, 17322550753, 33890757331
OFFSET
1,1
COMMENTS
Column 6 of A281056.
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) +3*a(n-2) -11*a(n-3) -9*a(n-4) +15*a(n-5) +20*a(n-6) +3*a(n-7) -18*a(n-8) -27*a(n-9) -9*a(n-10) +15*a(n-11) +20*a(n-12) +12*a(n-13) -7*a(n-15) -6*a(n-16) -3*a(n-17) -a(n-18) for n>21
EXAMPLE
Some solutions for n=4
..0..1..0..1..0..1. .0..1..0..1..0..1. .0..0..1..0..1..0. .0..1..0..1..0..1
..0..1..0..1..0..0. .1..1..0..1..0..1. .1..0..1..0..1..0. .0..1..0..0..1..0
..1..0..1..0..1..0. .0..1..0..1..0..1. .0..1..1..0..0..1. .0..1..1..0..0..1
..1..0..1..0..0..1. .1..0..0..1..0..1. .0..0..1..1..0..0. .0..0..1..1..0..0
CROSSREFS
Cf. A281056.
Sequence in context: A229631 A206307 A229475 * A056238 A335158 A221822
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 13 2017
STATUS
approved