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A304298
Number of nX4 0..1 arrays with every element unequal to 1, 2, 5 or 8 king-move adjacent elements, with upper left element zero.
1
2, 1, 5, 4, 13, 30, 43, 129, 245, 519, 1254, 2525, 5707, 12749, 27205, 60962, 133639, 292125, 647249, 1418245, 3119874, 6875729, 15098235, 33237465, 73128441, 160782286, 353832779, 778266279, 1711882901, 3766329669, 8284438272
OFFSET
1,1
COMMENTS
Column 4 of A304302.
LINKS
FORMULA
Empirical: a(n) = a(n-1) +a(n-2) +5*a(n-3) -2*a(n-4) +2*a(n-5) -8*a(n-6) -2*a(n-7) -a(n-8) -4*a(n-9) -a(n-10) -2*a(n-12) -a(n-13) -a(n-14) -a(n-15) for n>19
EXAMPLE
Some solutions for n=5
..0..0..0..0. .0..0..0..0. .0..0..1..0. .0..1..0..0. .0..0..0..0
..1..0..0..1. .1..0..0..1. .1..0..0..0. .0..0..0..1. .1..0..0..1
..0..0..0..0. .0..0..0..0. .0..0..0..0. .0..0..0..0. .0..0..0..0
..0..0..0..1. .1..0..0..0. .1..0..0..1. .1..0..0..1. .1..0..0..1
..0..1..0..0. .0..0..1..0. .0..0..0..0. .0..0..0..0. .0..0..0..0
CROSSREFS
Cf. A304302.
Sequence in context: A120924 A079285 A240607 * A309976 A257516 A346800
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 10 2018
STATUS
approved