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 A206353 Number of n X 2 0..4 arrays with no element equal to another within two positions in the same row or column, and new values 0..4 introduced in row major order. 1
 1, 4, 17, 120, 884, 6558, 48680, 361422, 2683328, 19922214, 147910952, 1098154590, 8153170064, 60532632918, 449420225720, 3336688521102, 24773006668448, 183925426722054, 1365541253642312, 10138363949208510, 75271562311604144 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Column 2 of A206359. LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 6*a(n-1) + 13*a(n-2) - 18*a(n-3) for n>5. Empirical g.f.: x*(1 - 2*x - 20*x^2 - 16*x^3 + 15*x^4) / ((1 - x)*(1 - 5*x - 18*x^2)). - Colin Barker, Jun 15 2018 EXAMPLE Some solutions for n=4: ..0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1 ..1..0....1..2....2..3....1..0....1..2....1..0....2..3....1..2....2..3....1..0 ..2..3....2..0....3..2....2..3....3..4....2..3....1..4....2..3....4..2....2..3 ..3..4....3..4....4..0....4..1....2..3....3..1....0..1....3..0....0..1....0..4 CROSSREFS Cf. A206359. Sequence in context: A240323 A335945 A360879 * A260694 A032115 A054927 Adjacent sequences: A206350 A206351 A206352 * A206354 A206355 A206356 KEYWORD nonn AUTHOR R. H. Hardin, Feb 06 2012 STATUS approved

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Last modified May 29 17:30 EDT 2023. Contains 363042 sequences. (Running on oeis4.)