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A253751 Number of (3+1)X(n+1) 0..2 arrays with every 2X2 subblock ne-sw antidiagonal difference nondecreasing horizontally and nw+se diagonal sum nondecreasing vertically 1
1998, 16625, 77414, 247252, 583698, 1204422, 2363797, 4404701, 7884084, 14024725, 25106259, 45066424, 81275585, 147957366, 271721790, 502088605, 932375372, 1738806953, 3252858270, 6097945230, 11448266368, 21515673019, 40464913904 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 3 of A253749

LINKS

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

FORMULA

Empirical: a(n) = 5*a(n-1) -10*a(n-2) +12*a(n-3) -8*a(n-4) -10*a(n-5) +35*a(n-6) -47*a(n-7) +42*a(n-8) -10*a(n-9) -40*a(n-10) +68*a(n-11) -68*a(n-12) +40*a(n-13) +10*a(n-14) -42*a(n-15) +47*a(n-16) -35*a(n-17) +10*a(n-18) +8*a(n-19) -12*a(n-20) +10*a(n-21) -5*a(n-22) +a(n-23) for n>30

EXAMPLE

Some solutions for n=3

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

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

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

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

CROSSREFS

Sequence in context: A171467 A258106 A253744 * A031808 A167292 A230202

Adjacent sequences:  A253748 A253749 A253750 * A253752 A253753 A253754

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 11 2015

STATUS

approved

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Last modified August 4 16:18 EDT 2021. Contains 346447 sequences. (Running on oeis4.)