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A302213
Number of 3Xn 0..1 arrays with every element equal to 0, 2 or 3 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.
1
4, 2, 16, 5, 32, 22, 72, 101, 216, 486, 968, 2541, 5598, 14718, 35506, 91947, 231984, 597758, 1533828, 3954067, 10201602, 26336704, 68062810, 175893407, 454813604, 1176002162, 3041473404, 7866219629, 20346282584, 52627527962, 136129978706
OFFSET
1,1
COMMENTS
Row 3 of A302212.
LINKS
FORMULA
Empirical: a(n) = 4*a(n-1) +4*a(n-2) -29*a(n-3) -3*a(n-4) +96*a(n-5) -14*a(n-6) -187*a(n-7) +39*a(n-8) +246*a(n-9) -52*a(n-10) -230*a(n-11) +48*a(n-12) +146*a(n-13) -29*a(n-14) -57*a(n-15) +9*a(n-16) +12*a(n-17) -a(n-18) -a(n-19) for n>20
EXAMPLE
Some solutions for n=5
..0..1..1..0..1. .0..1..0..0..0. .0..0..0..1..0. .0..0..1..1..0
..0..1..1..0..1. .1..1..1..0..1. .1..0..1..1..1. .1..0..0..1..1
..1..1..0..0..0. .0..1..1..0..1. .1..0..1..1..0. .0..0..1..1..0
CROSSREFS
Cf. A302212.
Sequence in context: A285362 A109922 A090640 * A090881 A191452 A348685
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 03 2018
STATUS
approved