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A258550 Number of (n+1) X (4+1) 0..1 arrays with every 2 X 2 subblock ne-sw antidiagonal difference nondecreasing horizontally and nw+se diagonal sum nondecreasing vertically. 1
228, 344, 985, 1891, 3754, 6196, 9688, 14216, 20285, 27687, 36927, 48039, 61576, 77378, 95998, 117518, 142539, 170949, 203349, 239869, 281158, 327152, 378500, 435380, 498489, 567811, 644043, 727411, 818660, 917822, 1025642, 1142394 (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) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - 4*a(n-5) + 6*a(n-6) - 4*a(n-7) + a(n-8) for n>12.

Empirical g.f.: x*(228 - 568*x + 977*x^2 - 897*x^3 + 724*x^4 - 502*x^5 - 128*x^6 + 412*x^7 - 433*x^8 + 357*x^9 - 136*x^10 + 14*x^11) / ((1 - x)^5*(1 + x)*(1 + x^2)). - Colin Barker, Dec 21 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Column 4 of A258554.

Sequence in context: A090943 A252451 A305063 * A335269 A252228 A252221

Adjacent sequences:  A258547 A258548 A258549 * A258551 A258552 A258553

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jun 03 2015

STATUS

approved

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Last modified September 25 04:20 EDT 2021. Contains 347652 sequences. (Running on oeis4.)