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A266019 Number of nX2 integer arrays with each element equal to the number of horizontal, vertical and antidiagonal neighbors exactly one smaller than itself. 1
3, 7, 14, 42, 99, 259, 719, 1784, 4792, 12479, 32263, 86025, 222663, 585072, 1535472, 4002444, 10527738, 27516774, 72060109, 188952481, 494214824, 1295507675, 3392305134, 8882420053, 23272852966, 60933892273, 159611564865, 418043981246 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A266025.

LINKS

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

FORMULA

Empirical: a(n) = a(n-1) +2*a(n-2) +6*a(n-3) -a(n-4) +20*a(n-5) -25*a(n-6) -37*a(n-7) -53*a(n-8) -52*a(n-9) +47*a(n-10) +74*a(n-11) +77*a(n-12) +30*a(n-13) -29*a(n-14) -34*a(n-15) -34*a(n-16) -a(n-17) -6*a(n-18) +11*a(n-19) +a(n-20) +a(n-21)

EXAMPLE

Some solutions for n=4

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

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

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

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

CROSSREFS

Cf. A266025.

Sequence in context: A146936 A184264 A298913 * A146155 A106363 A128658

Adjacent sequences:  A266016 A266017 A266018 * A266020 A266021 A266022

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 20 2015

STATUS

approved

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Last modified September 24 01:21 EDT 2020. Contains 337315 sequences. (Running on oeis4.)