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A227431
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Fibonacci differences triangle, T(n,k), k<=n, where column k holds the k-th difference of A000045, read by rows.
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4
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1, 1, 0, 2, 1, 1, 3, 1, 0, -1, 5, 2, 1, 1, 2, 8, 3, 1, 0, -1, -3, 13, 5, 2, 1, 1, 2, 5, 21, 8, 3, 1, 0, -1, -3, -8, 34, 13, 5, 2, 1, 1, 2, 5, 13, 55, 21, 8, 3, 1, 0, -1, -3, -8, -21, 89, 34, 13, 5, 2, 1, 1, 2, 5, 13, 34, 144, 55, 21, 8, 3, 1, 0, -1, -3, -8, -21
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OFFSET
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1,4
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COMMENTS
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Consecutive columns (i.e., k = 1, 2, 3, ...) shift the Fibonacci sequence down by 2 indices.
Diagonal (n = k) produces Fibonacci numbers at increasingly negative indices for n = k > 2. See A039834.
Row sums equal A005013(n), which equals Fibonacci A000045(n), if n is even, and equals Lucas numbers A000204(n) if n is odd.
(Rows that sum to Lucas numbers have all positive values.)
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LINKS
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FORMULA
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T(n,1) = F(n) for n > 0, where F(n) = A000045(n), T(n,k) = T(n,k-1) - T(n-1,k-1).
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EXAMPLE
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1
1 0
2 1 1
3 1 0 -1
5 2 1 1 2
8 3 1 0 -1 -3
13 5 2 1 1 2 5
21 8 3 1 0 -1 -3 -8
34 13 5 2 1 1 2 5 13
55 21 8 3 1 0 -1 -3 -8 -21
89 34 13 5 2 1 1 2 5 13 34
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MATHEMATICA
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Flatten[Table[Fibonacci[Range[n, -n + 1, -2]], {n, 15}]] (* T. D. Noe, Jul 26 2013 *)
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PROG
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(Haskell)
a227431 n k = a227431_tabl !! (n-1) !! (k-1)
a227431_row n = a227431_tabl !! (n-1)
a227431_tabl = h [] 0 1 where
h row u v = row' : h row' v (u + v) where row' = scanl (-) v row
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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