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A228217
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Number of second differences of arrays of length n+2 of numbers in 0..7
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1
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29, 519, 7309, 88215, 951049, 9399615, 86929081, 766106895, 6537612649, 54701587935, 452558355481, 3719467815855, 30436607366089, 248242046141055, 2019169299698041, 16385984911571535, 132716292890482729
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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) = 15*a(n-1) -56*a(n-2) for n>15
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EXAMPLE
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Some solutions for n=4
.-8....0...-8....1....4..-11....3....7..-10...-1...-4....4...-2....8...-3...-9
.13...-2...-1....5...-3....7....0...-4....3...10....8...-2...-8...-4....5...11
-12...-3....4...-7...-4...-3...-5....8...-1..-13....0...-3....7...-8....3...-1
..8....9....2....4....1....3...-2..-11....6...12..-10...-3....7...11...-3...-4
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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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