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 A240322 Number of n X 2 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, modulo 4. 1
 2, 5, 17, 37, 80, 213, 443, 1028, 2511, 5370, 12742, 29737, 65687, 155443, 355668, 803696, 1883007, 4285398, 9805203, 22760901, 51853646, 119272787, 275149593, 628629688, 1447871151, 3328934761, 7625189365, 17555754237, 40308328871 (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) = 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) for n>14. Empirical g.f.: x*(2 + 5*x + 13*x^2 + 7*x^3 - 2*x^4 - 16*x^5 - 15*x^6 - 3*x^7 + 2*x^8 + 11*x^9 + 13*x^10 + 3*x^11 - 3*x^12 - 4*x^13) / (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: ..3..2....3..2....3..2....3..2....3..2....2..3....2..3....2..3....2..3....2..3 ..2..1....2..1....2..3....2..1....2..1....3..2....3..0....3..0....3..0....3..0 ..3..1....2..0....3..2....3..2....3..0....2..3....3..2....3..1....2..1....3..1 ..2..1....2..0....2..1....3..2....3..2....2..1....3..2....3..1....2..1....2..3 CROSSREFS Column 2 of A240327. Sequence in context: A107630 A078523 A078324 * A346809 A276460 A002496 Adjacent sequences: A240319 A240320 A240321 * A240323 A240324 A240325 KEYWORD nonn AUTHOR R. H. Hardin, Apr 03 2014 STATUS approved

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Last modified January 31 15:47 EST 2023. Contains 359976 sequences. (Running on oeis4.)