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A319812
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Square array read by antidiagonals: T(n,k) = (1 + i)-adic valuation of n + k*i, n >= 0, k >= 0, or -1 if n + k*i = 0.
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0
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-1, 0, 0, 2, 1, 2, 0, 0, 0, 0, 4, 1, 3, 1, 4, 0, 0, 0, 0, 0, 0, 2, 1, 2, 1, 2, 1, 2, 0, 0, 0, 0, 0, 0, 0, 0, 6, 1, 3, 1, 5, 1, 3, 1, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 1, 3, 1, 4, 1, 3, 1, 4, 1, 3, 1, 4
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OFFSET
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0,4
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COMMENTS
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Equivalently, T(n,k) = 2-adic valuation of n^2 + k^2.
Table is symmetric with respect to the main diagonal. For any Gaussian integer z = x + y*i, its (1 + i)-adic valuation is T(|x|,|y|) if z != 0 and +oo if z = 0.
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LINKS
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FORMULA
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For n + k*i != 0:
T(n,k) = v(n^2 + k^2, 2) where v(k, 2) = A007814(k) is the 2-adic valuation of k.
T(n,k) = 2*min{v(n, 2), v(k, 2)} if v(n, 2) != v(k, 2), otherwise v(n, 2) + v(k, 2) + 1. Here v(0, 2) = +oo.
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EXAMPLE
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Table begins
X 0 2 0 4 0 2 0 6 0 2 0 4 0 2 0 8 ...
0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 ...
2 0 3 0 2 0 3 0 2 0 3 0 2 0 3 0 2 ...
0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 ...
4 0 2 0 5 0 2 0 4 0 2 0 5 0 2 0 4 ...
0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 ...
2 0 3 0 2 0 3 0 2 0 3 0 2 0 3 0 2 ...
0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 ...
6 0 2 0 4 0 2 0 7 0 2 0 4 0 2 0 6 ...
0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 ...
2 0 3 0 2 0 3 0 2 0 3 0 2 0 3 0 2 ...
0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 ...
4 0 2 0 5 0 2 0 4 0 2 0 5 0 2 0 4 ...
0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 ...
2 0 3 0 2 0 3 0 2 0 3 0 2 0 3 0 2 ...
0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 ...
8 0 2 0 4 0 2 0 6 0 2 0 4 0 2 0 9 ...
...
(X denotes that (1 + i)-adic valuation of 0 is +oo)
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PROG
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(PARI) T(n, k) = valuation(n^2+k^2, 2)
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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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