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A281125
Number of nX3 0..2 arrays with no element equal to more than one of its horizontal, vertical and antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.
1
1, 28, 574, 5590, 48828, 394202, 3042893, 22772368, 166675727, 1199580226, 8520471567, 59882031330, 417204045166, 2885615431576, 19835570766874, 135626535970070, 923084270635629, 6257223861792470, 42263904928277217
OFFSET
1,2
COMMENTS
Column 3 of A281129.
LINKS
FORMULA
Empirical: a(n) = 9*a(n-1) -70*a(n-3) -176*a(n-4) -366*a(n-5) -101*a(n-6) +541*a(n-7) +111*a(n-8) -731*a(n-9) -2114*a(n-10) -1900*a(n-11) +3502*a(n-12) +2900*a(n-13) -4597*a(n-14) -2319*a(n-15) +2436*a(n-16) +220*a(n-17) +76*a(n-18) +1492*a(n-19) +672*a(n-20) +160*a(n-21) +192*a(n-22) +64*a(n-23) for n>30
EXAMPLE
Some solutions for n=4
..0..1..2. .0..1..2. .0..1..2. .0..1..2. .0..1..2. .0..1..0. .0..1..2
..0..1..0. .2..0..1. .2..1..2. .0..2..1. .0..2..1. .2..0..2. .1..0..0
..2..0..2. .2..2..0. .1..0..1. .1..2..1. .1..1..2. .2..0..1. .0..1..1
..1..1..1. .1..0..1. .0..1..0. .0..0..2. .2..1..2. .1..2..1. .2..2..0
CROSSREFS
Cf. A281129.
Sequence in context: A145149 A062142 A240800 * A234618 A107397 A053110
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 15 2017
STATUS
approved