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A302821 Number of 3Xn 0..1 arrays with every element equal to 0, 1, 2, 4 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. 1
4, 25, 75, 220, 731, 2419, 7900, 25645, 83685, 273504, 893195, 2915411, 9518108, 31079021, 101478805, 331335348, 1081839931, 3532345439, 11533574036, 37658571753, 122959986781, 401480186136, 1310884882811, 4280209057195 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 3 of A302820.

LINKS

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

FORMULA

Empirical: a(n) = 6*a(n-1) -9*a(n-2) +2*a(n-4) -18*a(n-5) +37*a(n-6) +34*a(n-7) +5*a(n-8) -52*a(n-9) -118*a(n-10) -24*a(n-11) +190*a(n-12) +10*a(n-13) -68*a(n-14) +12*a(n-15) for n>16

EXAMPLE

Some solutions for n=5

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

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

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

CROSSREFS

Cf. A302820.

Sequence in context: A298282 A077205 A180569 * A125309 A273361 A266126

Adjacent sequences:  A302818 A302819 A302820 * A302822 A302823 A302824

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 13 2018

STATUS

approved

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Last modified November 30 08:19 EST 2021. Contains 349419 sequences. (Running on oeis4.)