A258538 - OEIS

A258538

Number of (n+2) X (1+2) 0..1 arrays with no 3 x 3 subblock diagonal sum less than the antidiagonal sum or central row sum equal to the central column sum.

220, 784, 2520, 8100, 25056, 77284, 234848, 712336, 2148108, 6471936, 19455312, 58461316, 175520864, 526886116, 1581124008, 4744454400, 14234924508, 42708355600, 128130243176, 384402480004, 1153224445824, 3459711600900

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OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 5*a(n-1) - 32*a(n-3) + 34*a(n-4) + 54*a(n-5) - 96*a(n-6) + 63*a(n-8) - 27*a(n-9).

Empirical g.f.: 4*x*(55 - 79*x - 350*x^2 + 635*x^3 + 541*x^4 - 1473*x^5 + 183*x^6 + 918*x^7 - 432*x^8) / ((1 - x)^3*(1 + x)*(1 - 3*x)*(1 - 3*x^2)^2). - Colin Barker, Dec 21 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

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

CROSSREFS

Column 1 of A258545.

Sequence in context: A135807 A258545 A257361 * A257354 A102073 A234969

Adjacent sequences: A258535 A258536 A258537 * A258539 A258540 A258541

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jun 02 2015

STATUS

approved