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A201092
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Number of -n..n arrays of 7 elements with first and second differences also in -n..n.
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1
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169, 5089, 50391, 286207, 1150785, 3681179, 9975741, 23891417, 51927841, 104482217, 197273691, 353343429, 605118809, 997367601, 1589978367, 2462102871, 3715701055, 5481137105, 7921503361, 11239970929, 15684870457, 21559136673
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = -a(n-1) +a(n-2) +3*a(n-3) +4*a(n-4) +2*a(n-5) -2*a(n-6) -8*a(n-7) -11*a(n-8) -7*a(n-9) +2*a(n-10) +12*a(n-11) +18*a(n-12) +16*a(n-13) +3*a(n-14) -11*a(n-15) -20*a(n-16) -20*a(n-17) -11*a(n-18) +3*a(n-19) +16*a(n-20) +18*a(n-21) +12*a(n-22) +2*a(n-23) -7*a(n-24) -11*a(n-25) -8*a(n-26) -2*a(n-27) +2*a(n-28) +4*a(n-29) +3*a(n-30) +a(n-31) -a(n-32) -a(n-33).
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EXAMPLE
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Some solutions for n=3
..3...-2...-1...-1....0....2....1....3...-3...-2...-1....2....0....2...-1....3
..0...-2....1...-2...-1....2....3....1...-2....1...-2...-1....1...-1....2....2
..0...-1....0...-1...-1....1....3....0...-3....2...-1...-2....3...-1....3....2
..0...-1....2....1....0....2....0....1...-1....1....1....0....3....0....3....2
.-1....2....2....2....1....0...-3....1...-1...-2....2....1....3....1....3....2
..0....2....0....2....0....0...-3....0...-2...-2....1...-1....0....0....1...-1
.-1....2...-2....0....0...-2...-2....1....0....0....3...-2...-1....2...-2...-1
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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