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A304038
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Irregular triangle T(n,k) read by rows: first row is 0, n-th row (n > 1) lists indices of distinct primes dividing n.
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44
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0, 1, 2, 1, 3, 1, 2, 4, 1, 2, 1, 3, 5, 1, 2, 6, 1, 4, 2, 3, 1, 7, 1, 2, 8, 1, 3, 2, 4, 1, 5, 9, 1, 2, 3, 1, 6, 2, 1, 4, 10, 1, 2, 3, 11, 1, 2, 5, 1, 7, 3, 4, 1, 2, 12, 1, 8, 2, 6, 1, 3, 13, 1, 2, 4, 14, 1, 5, 2, 3, 1, 9, 15, 1, 2, 4, 1, 3, 2, 7, 1, 6, 16, 1, 2, 3, 5, 1, 4, 2, 8, 1, 10, 17, 1, 2, 3, 18, 1, 11
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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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The irregular triangle begins:
1: {0}
2: {1}
3: {2}
4: {1}
5: {3}
6: {1, 2}
7: {4}
8: {1}
9: {2}
10: {1, 3}
11: {5}
12: {1, 2}
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MATHEMATICA
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Flatten[Table[PrimePi[FactorInteger[n][[All, 1]]], {n, 1, 62}]]
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CROSSREFS
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KEYWORD
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nonn,tabf
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AUTHOR
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STATUS
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approved
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