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 A239851 Number of n X 1 0..3 arrays with no element equal to zero plus the sum of elements to its left or zero plus the sum of elements above it or one plus the sum of the elements diagonally to its northwest or one plus the sum of the elements antidiagonally to its northeast, modulo 4. 10
 2, 2, 4, 6, 8, 14, 20, 30, 48, 70, 108, 166, 248, 382, 580, 878, 1344, 2038, 3100, 4726, 7176, 10926, 16628, 25278, 38480, 58534, 89036, 135494, 206104, 313566, 477092, 725774, 1104224, 1679958, 2555772, 3888406, 5915688, 8999950, 13692500 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 1 of A239858. LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = a(n-2) +2*a(n-3). Empirical g.f.: 2*x*(1 + x + x^2) / (1 - x^2 - 2*x^3). - Colin Barker, Feb 18 2018 EXAMPLE All solutions for n=4: ..3....3....2....2....2....3 ..2....2....3....3....3....2 ..3....3....3....2....3....2 ..2....3....3....2....2....2 CROSSREFS Sequence in context: A291055 A266949 A255710 * A153958 A216214 A269298 Adjacent sequences:  A239848 A239849 A239850 * A239852 A239853 A239854 KEYWORD nonn AUTHOR R. H. Hardin, Mar 28 2014 STATUS approved

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Last modified October 23 08:57 EDT 2019. Contains 328345 sequences. (Running on oeis4.)