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A295527 Number of nX4 0..1 arrays with each 1 horizontally or vertically adjacent to 1, 2 or 4 1s. 1
7, 87, 774, 7071, 64189, 588529, 5400933, 49414072, 452274232, 4141178883, 37915462501, 347125927592, 3178043159907, 29096212160166, 266386963989786, 2438870587989546, 22328758454009391, 204428063085791198 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Column 4 of A295531.
LINKS
FORMULA
Empirical: a(n) = 6*a(n-1) +13*a(n-2) +115*a(n-3) +249*a(n-4) +426*a(n-5) -1288*a(n-6) -1624*a(n-7) +5590*a(n-8) +6289*a(n-9) -7886*a(n-10) -8123*a(n-11) +5854*a(n-12) +3323*a(n-13) -13470*a(n-14) -5787*a(n-15) +8339*a(n-16) -8574*a(n-17) -31382*a(n-18) -19075*a(n-19) +1988*a(n-20) +11913*a(n-21) -2666*a(n-22) +8280*a(n-23) +11515*a(n-24) +16869*a(n-25) +5768*a(n-26) -4269*a(n-27) -10768*a(n-28) -4992*a(n-29) +1675*a(n-30) +2329*a(n-31) +1426*a(n-32) -22*a(n-33) +215*a(n-34) +a(n-35) -79*a(n-36) -387*a(n-37) -93*a(n-38) +30*a(n-39) +31*a(n-40) +8*a(n-41) -8*a(n-42) -3*a(n-43) +a(n-45)
EXAMPLE
Some solutions for n=5
..0..1..1..0. .0..1..1..0. .0..1..1..1. .0..1..0..0. .0..0..0..0
..0..0..1..0. .0..0..1..0. .0..0..0..1. .1..1..0..0. .1..0..1..1
..1..0..1..0. .0..1..1..1. .0..0..0..0. .1..0..1..0. .1..0..1..0
..1..0..0..1. .1..1..1..0. .0..1..1..0. .0..0..1..1. .0..1..0..1
..1..0..1..1. .0..1..0..0. .1..1..0..0. .1..1..0..0. .0..1..0..1
CROSSREFS
Cf. A295531.
Sequence in context: A254473 A183613 A295036 * A173812 A199027 A360237
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 23 2017
STATUS
approved

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Last modified February 22 12:31 EST 2024. Contains 370255 sequences. (Running on oeis4.)