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A207110 Number of n X 7 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 1 1 0 vertically 1
25, 625, 3399, 11511, 30415, 68737, 139341, 260597, 457869, 765241, 1227499, 1902387, 2863155, 4201417, 6030337, 8488161, 11742113, 15992673, 21478255, 28480303, 37328823, 48408369, 62164501, 79110733, 99835989, 125012585 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 7 of A207111.

LINKS

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

FORMULA

Empirical: a(n) = (1/280)*n^7 + (7/45)*n^6 + (47/15)*n^5 + (206/9)*n^4 + (4111/120)*n^3 - (1037/45)*n^2 - (4493/210)*n + 9.

Conjectures from Colin Barker, Jun 19 2018: (Start)

G.f.: x*(25 + 425*x - 901*x^2 + 419*x^3 + 249*x^4 - 269*x^5 + 79*x^6 - 9*x^7) / (1 - x)^8.

a(n) = 8*a(n-1) - 28*a(n-2) + 56*a(n-3) - 70*a(n-4) + 56*a(n-5) - 28*a(n-6) + 8*a(n-7) - a(n-8) for n>8.

(End)

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Cf. A207111.

Sequence in context: A207367 A207499 A207241 * A207466 A207701 A207906

Adjacent sequences:  A207107 A207108 A207109 * A207111 A207112 A207113

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 15 2012

STATUS

approved

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Last modified October 26 22:19 EDT 2021. Contains 348269 sequences. (Running on oeis4.)