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A251050 Number of (n+1) X (3+1) 0..3 arrays with no 2 X 2 subblock having the sum of its diagonal elements greater than the absolute difference of its antidiagonal elements. 1
854, 4334, 10289, 24893, 53306, 114512, 237143, 498593, 1050871, 2263156, 4941211, 10973705, 24635963, 55831811, 127245743, 291219638, 668084936, 1535123866, 3530526046, 8124227554, 18700618529, 43053766658, 99130762082, 228260731322 (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) = 8*a(n-1) - 25*a(n-2) + 35*a(n-3) - 7*a(n-4) - 49*a(n-5) + 77*a(n-6) - 55*a(n-7) + 20*a(n-8) - 3*a(n-9) for n>12.

Empirical g.f.: x*(854 - 2498*x - 3033*x^2 + 21041*x^3 - 34325*x^4 + 22458*x^5 + 1073*x^6 - 9797*x^7 + 4718*x^8 - 398*x^9 - 153*x^10 + 3*x^11) / ((1 - x)^7*(1 - x - 3*x^2)). - Colin Barker, Nov 24 2018

EXAMPLE

Some solutions for n=4:

..0..1..1..3....0..2..3..3....0..1..2..3....0..0..0..3....0..2..2..2

..1..0..0..0....0..0..0..0....0..0..0..0....0..0..0..3....0..0..0..0

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

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

..3..0..0..0....1..1..1..1....3..1..1..0....3..0..0..1....3..2..2..0

CROSSREFS

Column 3 of A251055.

Sequence in context: A251148 A127593 A248856 * A085323 A185639 A105275

Adjacent sequences:  A251047 A251048 A251049 * A251051 A251052 A251053

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 29 2014

STATUS

approved

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Last modified September 22 18:56 EDT 2021. Contains 347608 sequences. (Running on oeis4.)