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A303243 Number of 3Xn 0..1 arrays with every element equal to 0, 2, 3, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. 1
4, 2, 18, 8, 60, 56, 236, 428, 1248, 3264, 8624, 24720, 65816, 187464, 509576, 1428608, 3932112, 10932480, 30245800, 83854984, 232353544, 643805072, 1784418352, 4944349600, 13703715720, 37974373160, 105243781928, 291657188656 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 3 of A303242.

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) +9*a(n-2) -28*a(n-3) -37*a(n-4) +117*a(n-5) +85*a(n-6) -280*a(n-7) -118*a(n-8) +424*a(n-9) +92*a(n-10) -428*a(n-11) -26*a(n-12) +300*a(n-13) +12*a(n-14) -172*a(n-15) +48*a(n-16) +24*a(n-17) -48*a(n-18) +8*a(n-20)

EXAMPLE

Some solutions for n=5

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

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

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

CROSSREFS

Cf. A303242.

Sequence in context: A285595 A255566 A302461 * A074676 A257505 A152883

Adjacent sequences:  A303240 A303241 A303242 * A303244 A303245 A303246

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 20 2018

STATUS

approved

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Last modified September 17 01:53 EDT 2021. Contains 347478 sequences. (Running on oeis4.)