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A251384
Number of (n+1) X (2+1) 0..2 arrays with every 2 X 2 subblock summing to 2 3 4 5 or 6.
1
571, 12457, 271393, 5914339, 128887759, 2808783981, 61210372853, 1333925956743, 29069557621363, 633497816232785, 13805489867099657, 300855891824364491, 6556396659359553239, 142880157321162697173, 3113713281361245496797
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 23*a(n-1) - 21*a(n-2) - 119*a(n-3) + 66*a(n-4) + 72*a(n-5) - 32*a(n-6).
Empirical g.f.: x*(571 - 676*x - 3127*x^2 + 1846*x^3 + 1912*x^4 - 864*x^5) / (1 - 23*x + 21*x^2 + 119*x^3 - 66*x^4 - 72*x^5 + 32*x^6). - Colin Barker, Nov 29 2018
EXAMPLE
Some solutions for n=2:
..1..2..1....2..0..2....1..2..2....0..2..1....1..2..1....2..2..2....1..0..1
..0..2..0....2..2..0....2..0..0....0..1..0....0..1..2....1..0..2....1..2..1
..2..0..0....1..1..2....0..1..1....1..1..2....1..1..2....1..2..1....2..1..0
CROSSREFS
Column 2 of A251390.
Sequence in context: A073036 A020381 A142767 * A076465 A144956 A178323
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 01 2014
STATUS
approved