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A136568
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Irregular triangle read by rows: row n contains the distinct values (in numerical order) making up the nonzero exponents in the prime-factorization of n. (Row 1 = (0).).
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2
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0, 1, 1, 2, 1, 1, 1, 3, 2, 1, 1, 1, 2, 1, 1, 1, 4, 1, 1, 2, 1, 1, 2, 1, 1, 1, 1, 3, 2, 1, 3, 1, 2, 1, 1, 1, 5, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 4, 2, 1, 2, 1, 1, 2, 1, 1, 3, 1, 1, 3, 1, 1, 1, 1, 2, 1, 1, 1, 2, 6, 1, 1, 1, 1, 2, 1, 1
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OFFSET
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1,4
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COMMENTS
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Row n, for n>=2, contains A071625(n) terms.
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LINKS
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EXAMPLE
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4200 = 2^3 * 3^1 * 5^2 * 7^1. The exponents of the prime factorization are therefore 3,1,2,1. Therefore row 4200 is (1,2,3).
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MATHEMATICA
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Join[{0}, Flatten[Rest[Table[Union[Transpose[FactorInteger[n]][[2]]], {n, 100}]]]] (* Harvey P. Dale, Mar 19 2013 *)
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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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EXTENSIONS
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STATUS
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approved
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