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A251147 Number of (n+1) X (6+1) 0..2 arrays with every 2 X 2 subblock summing to 4 and no 2 X 2 subblock having exactly two nonzero entries. 1
427, 565, 777, 1141, 1743, 2763, 4491, 7453, 12569, 21501, 37255, 65355, 116035, 208469, 378889, 696357, 1293471, 2426507, 4593563, 8767469, 16856057, 32613805, 63450647, 124026251, 243400723, 479274853, 946371561, 1873038613, 3714194799 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) - 5*a(n-3) + a(n-4) + 2*a(n-5).
Empirical g.f.: x*(427 - 716*x - 918*x^2 + 945*x^3 + 718*x^4) / ((1 - x)*(1 + x)*(1 - 2*x)*(1 - x - x^2)). - Colin Barker, Nov 26 2018
EXAMPLE
Some solutions for n=4:
..0..2..0..2..1..2..1....1..2..0..1..0..1..0....0..2..0..2..1..2..1
..1..1..1..1..0..1..0....0..1..1..2..1..2..1....1..1..1..1..0..1..0
..1..1..1..1..2..1..2....2..1..1..0..1..0..1....1..1..1..1..2..1..2
..1..1..1..1..0..1..0....1..0..2..1..2..1..2....1..1..1..1..0..1..0
..1..1..1..1..2..1..2....2..1..1..0..1..0..1....0..2..0..2..1..2..1
CROSSREFS
Column 6 of A251149.
Sequence in context: A227484 A272131 A054984 * A095811 A235217 A236383
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 30 2014
STATUS
approved

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Last modified March 2 21:07 EST 2024. Contains 370498 sequences. (Running on oeis4.)