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A318040 Number of nX3 0..1 arrays with every element unequal to 0, 2, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero. 1
1, 2, 8, 21, 86, 377, 1648, 7261, 31969, 140758, 619822, 2729394, 12018832, 52924798, 233054021, 1026252071, 4519095292, 19899811452, 87628711701, 385872557006, 1699187715083, 7482363905416, 32948548958936, 145088757010002 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Column 3 of A318045.
LINKS
FORMULA
Empirical: a(n) = 7*a(n-1) -15*a(n-2) +21*a(n-3) -25*a(n-4) +6*a(n-5) +9*a(n-6) -22*a(n-7) +44*a(n-8) -16*a(n-9) +32*a(n-10) -20*a(n-11) -31*a(n-12) -a(n-13) +2*a(n-14) -2*a(n-15) -18*a(n-16) +3*a(n-17) +12*a(n-18) +14*a(n-19) +3*a(n-20) -2*a(n-21) for n>23
EXAMPLE
Some solutions for n=5
..0..1..0. .0..1..0. .0..1..0. .0..1..0. .0..0..1. .0..1..0. .0..1..0
..1..1..0. .1..1..0. .1..0..1. .1..0..1. .0..1..0. .1..1..0. .1..0..1
..0..1..1. .0..0..1. .0..1..0. .0..0..0. .1..0..1. .0..1..1. .0..0..1
..0..0..0. .1..0..0. .1..1..0. .1..0..1. .0..0..1. .0..1..0. .1..1..0
..1..0..1. .1..0..1. .0..0..1. .0..1..1. .1..1..0. .1..0..1. .0..0..1
CROSSREFS
Cf. A318045.
Sequence in context: A219970 A107361 A185309 * A333705 A085077 A272827
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 13 2018
STATUS
approved

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Last modified June 23 18:37 EDT 2024. Contains 373653 sequences. (Running on oeis4.)