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 A240187 Number of n X 2 0..3 arrays with no element equal to zero plus the sum of elements to its left or one plus the sum of elements above it or three plus the sum of the elements diagonally to its northwest, modulo 4. 1
 1, 5, 12, 27, 73, 154, 358, 872, 1871, 4438, 10338, 22880, 54100, 123711, 279854, 655190, 1491102, 3413413, 7919449, 18045604, 41514375, 95741087, 218782546, 503899032, 1158409848, 2653808377, 6109601340, 14027233372, 32187863462 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 2*a(n-2) + 10*a(n-3) - a(n-4) - 5*a(n-5) - 15*a(n-6) + a(n-7) + 4*a(n-8) + 2*a(n-9) + 10*a(n-10) + 5*a(n-11) - 6*a(n-13). Empirical g.f.: x*(1 + 5*x + 10*x^2 + 7*x^3 - 10*x^5 - 6*x^6 - 5*x^7 - 6*x^8 + 4*x^9 + 4*x^10 + 6*x^11) / (1 - 2*x^2 - 10*x^3 + x^4 + 5*x^5 + 15*x^6 - x^7 - 4*x^8 - 2*x^9 - 10*x^10 - 5*x^11 + 6*x^13). - Colin Barker, Oct 27 2018 EXAMPLE Some solutions for n=4: ..2..0....2..0....2..0....2..0....2..0....2..0....2..0....2..0....2..0....2..0 ..1..0....1..0....1..3....2..0....2..0....1..3....1..3....2..0....2..3....1..3 ..2..3....2..3....1..2....2..0....2..3....2..1....2..3....2..0....2..3....2..3 ..1..2....1..3....2..3....1..0....2..3....1..2....1..0....2..0....1..0....1..2 CROSSREFS Column 2 of A240192. Sequence in context: A170828 A229422 A128439 * A172426 A145768 A162778 Adjacent sequences:  A240184 A240185 A240186 * A240188 A240189 A240190 KEYWORD nonn AUTHOR R. H. Hardin, Apr 02 2014 STATUS approved

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Last modified September 28 06:57 EDT 2021. Contains 347703 sequences. (Running on oeis4.)