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A211596
Number of -2..2 arrays x(i) of n+1 elements i=1..n+1 with set{t,u,v in 0,1}((x[i+t]+x[j+u]+x[k+v])*(-1)^(t+u+v)) having two, four, six, seven or eight distinct values for every i,j,k<=n
1
24, 76, 216, 580, 1528, 4004, 10420, 27296, 71226, 187728, 493256, 1309512, 3466430, 9262568, 24680896, 66292956, 177593130, 478917194, 1288401406, 3484849120, 9405820198, 25497846216, 68995125860, 187353048044, 507965003670
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 6*a(n-1) +9*a(n-2) -113*a(n-3) +45*a(n-4) +877*a(n-5) -925*a(n-6) -3715*a(n-7) +5272*a(n-8) +9518*a(n-9) -15967*a(n-10) -15379*a(n-11) +29010*a(n-12) +15821*a(n-13) -32561*a(n-14) -10205*a(n-15) +22254*a(n-16) +3946*a(n-17) -8792*a(n-18) -828*a(n-19) +1800*a(n-20) +72*a(n-21) -144*a(n-22)
EXAMPLE
Some solutions for n=5
..1....0...-1....1....1....1....2...-2....0....0....0....1....2...-2...-2...-2
..2....2...-1....0....1....2....2....0...-1....1...-2...-2....1...-2....2...-2
..0....2....1....1....2....2...-2...-1...-2....0...-2....1...-2...-2....2...-1
..2....0...-1...-2....0....1...-2....0....1...-1....0....2...-1...-1....2....2
..2....2...-1....1....2....2....2...-2....2....0...-2...-1....0...-2....2...-1
..0....2...-1....2....1....1....2....0....1....1...-2....2...-1....0....2....0
CROSSREFS
Sequence in context: A325958 A211574 A211588 * A214397 A048352 A144459
KEYWORD
nonn
AUTHOR
R. H. Hardin Apr 16 2012
STATUS
approved