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A284070 Number of nX3 0..1 arrays with no 1 equal to more than three of its horizontal, diagonal and antidiagonal neighbors, with the exception of exactly two elements. 1
0, 1, 15, 314, 3764, 37557, 353608, 3178404, 27582216, 233397609, 1936592863, 15815427428, 127479709618, 1016314018380, 8026733559938, 62881710177968, 489133088311108, 3781016346686269, 29064881546033136, 222309716942266766 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Column 3 of A284075.

LINKS

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

FORMULA

Empirical: a(n) = 21*a(n-1) -153*a(n-2) +484*a(n-3) -1254*a(n-4) +5199*a(n-5) -10697*a(n-6) +19671*a(n-7) -61194*a(n-8) +93379*a(n-9) -140298*a(n-10) +354402*a(n-11) -436616*a(n-12) +546228*a(n-13) -1123992*a(n-14) +1218808*a(n-15) -1193856*a(n-16) +1907040*a(n-17) -2009856*a(n-18) +1446528*a(n-19) -1456128*a(n-20) +1486336*a(n-21) -890880*a(n-22) +270336*a(n-23) -32768*a(n-24)

EXAMPLE

Some solutions for n=4

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

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

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

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

CROSSREFS

Cf. A284075.

Sequence in context: A135390 A105491 A158533 * A133766 A347980 A289951

Adjacent sequences:  A284067 A284068 A284069 * A284071 A284072 A284073

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 19 2017

STATUS

approved

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Last modified December 9 03:15 EST 2021. Contains 349625 sequences. (Running on oeis4.)