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A208636 Number of n X 7 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than one of its immediate leftward or upward or right-upward antidiagonal neighbors. 1
64, 191, 628, 2149, 7504, 26508, 94320, 337227, 1209736, 4349981, 15668332, 56505640, 203961088, 736686999, 2662084284, 9622940853, 34793691400, 125826023972, 455089068016, 1646125164451, 5954682909712, 21541486064685 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 7 of A208637.

LINKS

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

FORMULA

Empirical: a(n) = 8*a(n-1) - 21*a(n-2) + 20*a(n-3) - 5*a(n-4).

Empirical g.f.: x*(64 - 321*x + 444*x^2 - 144*x^3) / ((1 - 3*x + x^2)*(1 - 5*x + 5*x^2)). - Colin Barker, Jul 05 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Cf. A208637.

Sequence in context: A318342 A318074 A202332 * A135270 A045052 A195089

Adjacent sequences: A208633 A208634 A208635 * A208637 A208638 A208639

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 29 2012

STATUS

approved

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Last modified January 31 11:22 EST 2023. Contains 359971 sequences. (Running on oeis4.)