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A198648 Number of n X 1 0..6 arrays with values 0..6 introduced in row major order and each element equal to at least one horizontal or vertical neighbor. 1
0, 1, 1, 2, 3, 6, 11, 23, 47, 103, 226, 518, 1200, 2867, 6946, 17233, 43385, 111354, 289861, 766767, 2054605, 5579891, 15325432, 42559486, 119312586, 337469019, 961850000, 2760643085, 7971239103, 23140321458, 67486362815, 197615025815 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

Column 1 of A198654.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n) = 6*a(n-1) +a(n-2) -60*a(n-3) +50*a(n-4) +226*a(n-5) -231*a(n-6) -416*a(n-7) +361*a(n-8) +388*a(n-9) -180*a(n-10) -144*a(n-11) for n>12.

Empirical g.f.: x^2*(1 - 5*x - 5*x^2 + 50*x^3 - 4*x^4 - 184*x^5 + 36*x^6 + 303*x^7 - 3*x^8 - 189*x^9 - 53*x^10) / ((1 - x)*(1 + x)*(1 - 2*x)*(1 + 2*x)*(1 - 3*x)*(1 - x - x^2)*(1 - x - 3*x^2)*(1 - x - 4*x^2)). - Colin Barker, May 15 2018

EXAMPLE

All solutions for n=5:

..0....0....0

..0....0....0

..0....0....1

..1....0....1

..1....0....1

CROSSREFS

Cf. A198654.

Sequence in context: A277795 A198662 A198620 * A198655 A211694 A303586

Adjacent sequences: A198645 A198646 A198647 * A198649 A198650 A198651

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 28 2011

STATUS

approved

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Last modified February 4 20:58 EST 2023. Contains 360082 sequences. (Running on oeis4.)