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 A240285 Number of 2 X n 0..3 arrays with no element equal to one plus the sum of elements to its left or two plus the sum of the elements above it or zero plus the sum of the elements diagonally to its northwest, modulo 4. 1
 2, 8, 19, 76, 181, 741, 1779, 7308, 17561, 72140, 173343, 712043, 1710905, 7027848, 16886555, 69364556, 166669597, 684625413, 1645022411, 6757226212, 16236307329, 66693560300, 160251722711, 658262849419, 1581678277825, 6497028751792 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 12*a(n-2) - 24*a(n-4) + 31*a(n-6) - 16*a(n-8). Empirical g.f.: x*(1 - x)*(2 + 10*x + 5*x^2 - 15*x^3 - 14*x^4 + 7*x^5 + 8*x^6) / (1 - 12*x^2 + 24*x^4 - 31*x^6 + 16*x^8). - Colin Barker, Oct 27 2018 EXAMPLE Some solutions for n=4: ..3..1..3..1....3..3..1..3....3..1..3..1....3..1..3..1....3..3..1..3 ..2..1..2..0....2..0..2..3....3..1..0..0....3..2..0..0....2..0..2..2 CROSSREFS Row 2 of A240284. Sequence in context: A026572 A074797 A248115 * A129445 A082821 A188893 Adjacent sequences:  A240282 A240283 A240284 * A240286 A240287 A240288 KEYWORD nonn AUTHOR R. H. Hardin, Apr 03 2014 STATUS approved

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Last modified September 24 22:46 EDT 2021. Contains 347651 sequences. (Running on oeis4.)