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A304258
Number of nX3 0..1 arrays with every element unequal to 2, 3, 5 or 7 king-move adjacent elements, with upper left element zero.
1
0, 4, 8, 13, 17, 26, 61, 120, 233, 515, 959, 2203, 4422, 9326, 20164, 40967, 89272, 185242, 392175, 835695, 1743530, 3727147, 7826272, 16565391, 35110869, 73906489, 156874751, 330846728, 699916420, 1480948392, 3126555973, 6619649700
OFFSET
1,2
COMMENTS
Column 3 of A304263.
LINKS
FORMULA
Empirical: a(n) = a(n-1) +5*a(n-2) -a(n-3) -13*a(n-4) +5*a(n-5) +10*a(n-6) -16*a(n-7) +4*a(n-8) +14*a(n-9) -10*a(n-10) -14*a(n-11) +14*a(n-12) +4*a(n-13) -5*a(n-14) +13*a(n-15) -2*a(n-17) for n>18
EXAMPLE
Some solutions for n=5
..0..1..0. .0..0..0. .0..1..0. .0..1..1. .0..1..0. .0..1..0. .0..1..0
..1..1..1. .1..1..1. .1..1..1. .1..0..0. .1..0..1. .1..1..0. .0..1..1
..1..0..1. .0..1..0. .0..0..0. .1..1..0. .1..0..1. .1..0..0. .0..0..1
..0..0..0. .1..1..1. .0..0..0. .0..0..1. .1..1..1. .0..1..1. .1..1..0
..1..1..1. .0..0..0. .1..1..1. .1..0..1. .0..1..0. .0..1..0. .0..1..0
CROSSREFS
Cf. A304263.
Sequence in context: A311999 A312000 A312001 * A312002 A312003 A312004
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 09 2018
STATUS
approved