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 A198655 Number of n X 1 0..7 arrays with values 0..7 introduced in row major order and each element equal to at least one horizontal or vertical neighbor. 2
 0, 1, 1, 2, 3, 6, 11, 23, 47, 103, 226, 518, 1200, 2867, 6946, 17234, 43393, 111418, 290233, 768819, 2064637, 5626757, 15531220, 43432402, 122878654, 351665399, 1016952840, 2970387672, 8755225931, 26027153206, 77972236615, 235260594303 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS Column 1 of A198661. LINKS R. H. Hardin, Table of n, a(n) for n = 1..200 FORMULA Empirical: a(n) = 7*a(n-1) + a(n-2) - 97*a(n-3) + 105*a(n-4) + 531*a(n-5) - 757*a(n-6) - 1511*a(n-7) + 2143*a(n-8) + 2457*a(n-9) - 2689*a(n-10) - 2227*a(n-11) + 1198*a(n-12) + 840*a(n-13) for n>14. Empirical g.f.: x^2*(1 - 6*x - 6*x^2 + 85*x^3 - 25*x^4 - 476*x^5 + 247*x^6 + 1348*x^7 - 523*x^8 - 1959*x^9 + 157*x^10 + 1157*x^11 + 309*x^12) / ((1 - x)*(1 + x)*(1 - 2*x)*(1 - x - x^2)*(1 - x - 3*x^2)*(1 - x - 4*x^2)*(1 - x - 5*x^2)*(1 - x - 7*x^2)). - Colin Barker, Mar 02 2018 EXAMPLE All solutions for n=5: ..0....0....0 ..0....0....0 ..0....1....0 ..0....1....1 ..0....1....1 CROSSREFS Cf. A198661. Sequence in context: A198662 A198620 A198648 * A211694 A303586 A130131 Adjacent sequences: A198652 A198653 A198654 * A198656 A198657 A198658 KEYWORD nonn AUTHOR R. H. Hardin, Oct 28 2011 STATUS approved

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Last modified March 29 15:03 EDT 2023. Contains 361599 sequences. (Running on oeis4.)