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A301661
Number of nX7 0..1 arrays with every element equal to 0, 1 or 4 horizontally or vertically adjacent elements, with upper left element zero.
1
21, 22, 46, 89, 223, 696, 2335, 8380, 31001, 116558, 442314, 1686894, 6453062, 24725894, 94832665, 363935417, 1397133323, 5364622673, 20601302508, 79119265773, 303870780015, 1167097983033, 4482628695760, 17217197273712
OFFSET
1,1
COMMENTS
Column 7 of A301662.
LINKS
FORMULA
Empirical: a(n) = 5*a(n-1) -5*a(n-2) +14*a(n-3) -44*a(n-4) -2*a(n-5) -63*a(n-6) +117*a(n-7) +133*a(n-8) +386*a(n-9) +126*a(n-10) -575*a(n-11) -1064*a(n-12) -876*a(n-13) +203*a(n-14) +1305*a(n-15) +1617*a(n-16) +681*a(n-17) -882*a(n-18) -1502*a(n-19) -879*a(n-20) +297*a(n-21) +793*a(n-22) +486*a(n-23) +6*a(n-24) -191*a(n-25) -108*a(n-26) -14*a(n-27) +20*a(n-28) +12*a(n-29) +4*a(n-30) +a(n-31)
EXAMPLE
Some solutions for n=5
..0..1..0..1..0..1..0. .0..1..0..1..0..1..1. .0..1..0..0..1..0..1
..1..0..1..0..0..0..1. .1..0..1..1..1..0..0. .1..0..1..1..0..1..0
..0..0..0..1..0..1..0. .0..1..0..1..0..1..1. .0..1..0..0..1..1..1
..1..0..1..0..1..0..1. .1..1..1..0..1..0..0. .1..0..1..1..0..1..0
..0..1..0..1..0..1..0. .0..1..0..1..0..1..1. .0..1..0..0..1..0..1
CROSSREFS
Cf. A301662.
Sequence in context: A041884 A041882 A286762 * A281364 A041900 A041902
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 25 2018
STATUS
approved