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 A240266 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 one plus the sum of the elements diagonally to its northwest, modulo 4. 1
 4, 7, 14, 36, 72, 170, 411, 879, 2106, 4874, 10808, 25648, 58383, 132428, 310199, 704308, 1615735, 3746472, 8529529, 19647966, 45277950, 103456016, 238430432, 547803553, 1255188579, 2890336834, 6633676274, 15225374578, 35023723614 (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). Empirical g.f.: x*(1 + x)*(4 + 3*x + 3*x^2 - 21*x^3 - x^4 - 14*x^5 + 30*x^6 - 4*x^7 + 27*x^8 - x^9 + 2*x^10 - 12*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: ..3..2....3..2....3..2....3..0....2..3....3..2....3..0....2..0....2..3....3..2 ..3..1....2..1....3..2....3..2....2..1....2..1....2..3....2..0....2..1....3..2 ..2..1....3..2....2..3....2..1....3..0....3..1....3..1....3..2....3..2....2..3 ..2..0....3..1....3..1....2..1....2..3....2..3....3..2....2..1....3..2....3..2 CROSSREFS Column 2 of A240271. Sequence in context: A049945 A234576 A076586 * A064961 A137053 A214328 Adjacent sequences:  A240263 A240264 A240265 * A240267 A240268 A240269 KEYWORD nonn AUTHOR R. H. Hardin, Apr 03 2014 STATUS approved

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Last modified December 11 07:47 EST 2019. Contains 329914 sequences. (Running on oeis4.)