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 A220630 Number of ways to reciprocally link elements of an nX6 array either to themselves or to exactly two horizontal or antidiagonal neighbors 1
 1, 16, 158, 1665, 17527, 183961, 1932695, 20301254, 213251377, 2240062837, 23530357757, 247170637157, 2596361852466, 27273040848960, 286485012144200, 3009333012881404, 31611026051882958, 332052638832405598 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Column 6 of A220632 LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 7*a(n-1) +31*a(n-2) +57*a(n-3) +43*a(n-4) -3*a(n-5) -36*a(n-6) +19*a(n-7) -6*a(n-8) +a(n-9) EXAMPLE Some solutions for n=3 0=self 3=ne 4=w 6=e 7=sw (reciprocal directions total 10) .00.67.46.46.46.47...00.00.67.46.46.47...00.00.00.00.67.47...00.00.67.47.00.00 .36.46.47.00.37.00...00.36.46.47.37.00...00.00.00.36.34.00...00.37.37.67.46.47 .00.36.46.34.00.00...00.00.36.34.00.00...00.00.00.00.00.00...36.34.36.46.34.00 CROSSREFS Sequence in context: A211831 A036973 A101931 * A041005 A180798 A144453 Adjacent sequences:  A220627 A220628 A220629 * A220631 A220632 A220633 KEYWORD nonn AUTHOR R. H. Hardin Dec 17 2012 STATUS approved

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Last modified May 10 22:16 EDT 2021. Contains 343780 sequences. (Running on oeis4.)