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A232591 Number of (2+1) X (n+1) 0..2 arrays with every element next to itself plus and minus one within the range 0..2 horizontally or antidiagonally, with no adjacent elements equal. 1
2, 34, 12, 152, 108, 690, 744, 3232, 4516, 15592, 25724, 76914, 141516, 385622, 762648, 1955944, 4058152, 10001440, 21421592, 51425362, 112496648, 265415854, 588810972, 1373336224, 3075128652, 7118096080, 16037159652, 36935382354 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 5*a(n-2) + 4*a(n-3) - 3*a(n-4) - 12*a(n-5) - 3*a(n-6) + 6*a(n-7) + 6*a(n-8) + 2*a(n-9) for n>10.
Empirical g.f.: x*(1 + 17*x + x^2 - 13*x^3 - 41*x^4 + 4*x^5 + 23*x^6 + 20*x^7 + 2*x^8 - x^9) / (1 - 5*x^2 - 4*x^3 + 3*x^4 + 12*x^5 + 3*x^6 - 6*x^7 - 6*x^8 - 2*x^9). - Colin Barker, Oct 05 2018
EXAMPLE
Some solutions for n=7:
..2..1..0..2..1..0..1..0....0..1..2..0..1..0..1..2....2..1..0..1..2..0..1..2
..2..1..0..2..1..2..1..0....2..0..1..2..1..2..1..0....2..1..2..1..2..0..1..2
..0..2..1..0..1..2..1..2....1..2..1..0..1..0..1..2....0..1..0..1..2..0..1..2
CROSSREFS
Row 2 of A232589.
Sequence in context: A109336 A180342 A343905 * A098869 A131544 A123284
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 26 2013
STATUS
approved

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Last modified April 22 04:43 EDT 2024. Contains 371887 sequences. (Running on oeis4.)