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A251132 Number of (n+1) X (3+1) 0..2 arrays with no 2 X 2 subblock having the sum of its diagonal elements greater than the maximum of its antidiagonal elements. 1
369, 1002, 1997, 4110, 8050, 15830, 30770, 60088, 117492, 230956, 455680, 902602, 1792830, 3569098, 7116086, 14203652, 28370704, 56695536, 113333908, 226597798, 453110314, 906118110, 1812113626, 3624082160, 7247993420, 14495787220 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 6*a(n-1) - 13*a(n-2) + 10*a(n-3) + 5*a(n-4) - 14*a(n-5) + 9*a(n-6) - 2*a(n-7) for n>10.

Conjectures from Colin Barker, Nov 26 2018: (Start)

G.f.: x*(369 - 1212*x + 782*x^2 + 1464*x^3 - 2514*x^4 + 1146*x^5 + 62*x^6 - 114*x^7 - 5*x^8 + 2*x^9) / ((1 - x)^5*(1 + x)*(1 - 2*x)).

a(n) = (36*(-5+9*(-1)^n+9*2^(3+n)) + 202*n + 151*n^2 + 50*n^3 + 5*n^4) / 12 for n>3.

(End)

EXAMPLE

Some solutions for n=4:

..0..0..0..2....0..0..1..2....0..0..1..2....0..0..2..2....0..0..0..2

..0..0..0..0....1..1..1..1....1..0..1..0....0..0..2..0....0..0..0..1

..0..0..0..0....1..0..0..0....1..0..1..0....1..0..2..0....0..0..0..1

..2..2..2..2....1..0..0..0....2..0..1..0....1..0..2..0....1..0..0..1

..1..0..0..0....1..0..0..0....2..0..1..0....2..0..2..0....1..0..0..0

CROSSREFS

Column 3 of A251137.

Sequence in context: A294711 A062041 A205730 * A183351 A275170 A205911

Adjacent sequences:  A251129 A251130 A251131 * A251133 A251134 A251135

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 30 2014

STATUS

approved

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Last modified October 16 09:02 EDT 2021. Contains 348041 sequences. (Running on oeis4.)