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 A196850 Number of n X 2 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 3,1,0,2,4 for x=0,1,2,3,4. 2
 2, 11, 38, 136, 496, 1792, 6440, 23306, 84180, 303664, 1096874, 3960906, 14299036, 51633110, 186437376, 673147554, 2430568646, 8776143806, 31687921122, 114416191032, 413124704992, 1491673030176, 5386005309890, 19447328987316 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Every 0 is next to 0 3's, every 1 is next to 1 1's, every 2 is next to 2 0's, every 3 is next to 3 2's, every 4 is next to 4 4's. Column 2 of A196856. LINKS R. H. Hardin, Table of n, a(n) for n = 1..200 FORMULA Empirical: a(n) = a(n-1) + 4*a(n-2) + 17*a(n-3) + 10*a(n-4) - 3*a(n-5) + 2*a(n-6) + 2*a(n-7) for n>8. Empirical g.f.: x*(2 + 9*x + 19*x^2 + 20*x^3 + x^4 + 2*x^5 + x^6 - 6*x^7) / (1 - x - 4*x^2 - 17*x^3 - 10*x^4 + 3*x^5 - 2*x^6 - 2*x^7). - Colin Barker, Mar 01 2018 EXAMPLE Some solutions for n=4: ..0..0....1..1....1..1....2..0....1..1....1..1....2..0....0..0....2..0....0..0 ..1..0....0..0....0..0....0..0....0..2....0..2....0..1....0..0....0..0....2..0 ..1..0....2..0....0..1....0..0....2..0....0..0....0..1....2..1....0..1....2..0 ..0..0....1..1....0..1....1..1....1..1....0..2....0..0....0..1....0..1....0..2 CROSSREFS Cf. A196856. Sequence in context: A059673 A294152 A196701 * A203534 A166989 A143550 Adjacent sequences:  A196847 A196848 A196849 * A196851 A196852 A196853 KEYWORD nonn AUTHOR R. H. Hardin, Oct 06 2011 STATUS approved

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Last modified June 14 08:09 EDT 2021. Contains 345018 sequences. (Running on oeis4.)