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A230509 Number of n X 2 0..7 arrays x(i,j) with each element horizontally or vertically next to at least one element with value (x(i,j)+1) mod 8, and upper left element zero. 2
0, 0, 0, 2, 8, 32, 118, 440, 1664, 6354, 24360, 93440, 358246, 1372824, 5259424, 20147874, 77183048, 295680992, 1132742102, 4339515256, 16624624832, 63688678130, 243990165864, 934721535168, 3580899428294, 13718353772632 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

Column 2 of A230513.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 5*a(n-1) - 4*a(n-2) - 5*a(n-3) + 9*a(n-4) + 12*a(n-5).

Empirical g.f.: 2*x^4*(1 - x) / (1 - 5*x + 4*x^2 + 5*x^3 - 9*x^4 - 12*x^5). - Colin Barker, Mar 17 2018

EXAMPLE

All solutions for n=4:

..0..7....0..1

..1..6....7..2

..2..5....6..3

..3..4....5..4

CROSSREFS

Cf. A230513.

Sequence in context: A067897 A145682 A289451 * A099752 A230393 A230529

Adjacent sequences: A230506 A230507 A230508 * A230510 A230511 A230512

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 21 2013

STATUS

approved

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Last modified February 1 17:37 EST 2023. Contains 359993 sequences. (Running on oeis4.)