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A297989
Number of nX4 0..1 arrays with every element equal to 1, 2, 3 or 6 king-move adjacent elements, with upper left element zero.
4
2, 49, 146, 466, 1446, 4648, 14888, 47399, 150849, 480015, 1528351, 4868127, 15504952, 49377480, 157242432, 500744003, 1594669951, 5078421202, 16172807093, 51503968299, 164019559229, 522337092408, 1663436972579, 5297389242128
OFFSET
1,1
COMMENTS
Column 4 of A297993.
LINKS
FORMULA
Empirical: a(n) = 5*a(n-1) -6*a(n-2) +2*a(n-3) -5*a(n-4) +10*a(n-5) -19*a(n-6) -30*a(n-7) +29*a(n-8) +61*a(n-9) +81*a(n-10) -91*a(n-11) -78*a(n-12) -35*a(n-13) +86*a(n-14) +10*a(n-15) -35*a(n-16) -23*a(n-17) +16*a(n-18) +37*a(n-19) -32*a(n-20) +14*a(n-21) +6*a(n-22) -8*a(n-23) +4*a(n-24) for n>27
EXAMPLE
Some solutions for n=7
..0..1..0..0. .0..1..0..0. .0..0..0..0. .0..1..0..0. .0..0..0..0
..0..1..0..0. .0..1..0..1. .1..1..1..1. .0..0..1..0. .1..1..1..0
..0..1..1..1. .1..1..0..1. .1..0..0..1. .1..1..1..0. .0..0..0..1
..1..0..0..0. .1..0..0..1. .0..1..0..1. .0..0..0..0. .0..1..1..0
..0..1..1..1. .0..1..1..1. .0..1..1..1. .0..1..1..1. .0..1..0..0
..1..0..0..0. .1..0..0..0. .0..1..0..1. .1..0..0..0. .0..1..0..1
..0..1..1..1. .1..1..1..1. .0..1..0..0. .1..1..1..1. .1..1..0..1
CROSSREFS
Cf. A297993.
Sequence in context: A041287 A057563 A297819 * A028479 A189389 A001568
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 10 2018
STATUS
approved