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A258559 Number of (6+1) X (n+1) 0..1 arrays with every 2 X 2 subblock ne-sw antidiagonal difference nondecreasing horizontally and nw+se diagonal sum nondecreasing vertically. 1
988, 2530, 3980, 6196, 8339, 10854, 13833, 17058, 20414, 23858, 27446, 31237, 35188, 39256, 43497, 47970, 52632, 57440, 62450, 67721, 73210, 78874, 84769, 90954, 97386, 104022, 110918, 118133, 125624, 133348, 141361, 149722, 158388, 167316, 176562 (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) = 3*a(n-1) - 3*a(n-2) + a(n-3) + a(n-4) - 3*a(n-5) + 3*a(n-6) - a(n-7) for n>13.

Empirical g.f.: x*(988 - 434*x - 646*x^2 + 858*x^3 - 1827*x^4 + 879*x^5 + 738*x^6 - 1076*x^7 + 724*x^8 - 488*x^9 - 36*x^10 + 277*x^11 + 72*x^12) / ((1 - x)^4*(1 + x)*(1 + x^2)). - Colin Barker, Dec 22 2018

EXAMPLE

Some solutions for n=4:

..0..0..0..0..0....0..0..0..0..0....0..0..0..0..0....0..0..0..0..0

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

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

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

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

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

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

CROSSREFS

Row 6 of A258554.

Sequence in context: A045733 A250490 A258552 * A235762 A235545 A232429

Adjacent sequences:  A258556 A258557 A258558 * A258560 A258561 A258562

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jun 03 2015

STATUS

approved

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Last modified September 27 04:10 EDT 2021. Contains 347673 sequences. (Running on oeis4.)