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A088239
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Triangle read by rows: T(n,k) is the number of primes not less than n-k and not greater than n+k, 0<=k<n.
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0
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0, 1, 2, 1, 2, 3, 0, 2, 3, 4, 1, 1, 3, 4, 4, 0, 2, 2, 3, 4, 5, 1, 1, 2, 2, 4, 5, 6, 0, 1, 1, 3, 3, 5, 6, 6, 0, 0, 2, 2, 4, 4, 5, 6, 7, 0, 1, 1, 3, 3, 4, 4, 6, 7, 8, 1, 1, 2, 2, 3, 3, 5, 5, 7, 8, 8, 0, 2, 2, 2, 2, 4, 4, 6, 6, 7, 8, 9, 1, 1, 2, 2, 3, 3, 5, 5, 6, 6, 8, 9, 9, 0, 1, 1, 3, 3, 4, 4, 5, 5, 7, 7, 8, 9, 9
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text;
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OFFSET
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1,3
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LINKS
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FORMULA
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EXAMPLE
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Triangle begins:
0;
1, 2;
1, 2, 3;
0, 2, 3, 4;
1, 1, 3, 4, 4;
0, 2, 2, 3, 4, 5;
...
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MATHEMATICA
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T[n_, k_] := PrimePi[n+k] - PrimePi[n-k-1];
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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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