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A238689
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Table read by rows: first row is {1}; for n >1, T(n, k) is the k-th largest prime factor of n (repeated prime factors are counted repeatedly).
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3
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1, 2, 3, 2, 2, 5, 3, 2, 7, 2, 2, 2, 3, 3, 5, 2, 11, 3, 2, 2, 13, 7, 2, 5, 3, 2, 2, 2, 2, 17, 3, 3, 2, 19, 5, 2, 2, 7, 3, 11, 2, 23, 3, 2, 2, 2, 5, 5, 13, 2, 3, 3, 3, 7, 2, 2, 29, 5, 3, 2, 31, 2, 2, 2, 2, 2, 11, 3, 17, 2, 7, 5, 3, 3, 2, 2, 37, 19, 2, 13, 3, 5, 2, 2, 2
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OFFSET
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1,2
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COMMENTS
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n-th row has length 1 if n = 1, A001222(n) if n > 1.
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LINKS
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FORMULA
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Row n is row n of A027746 in reverse order.
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EXAMPLE
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Table begins:
1;
2;
3;
2,2;
5;
3,2;
7;
2,2,2;
3,3;
5,2;
...
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PROG
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(Haskell)
a238689_row 1 = [1]
a238689_row n = a n [] a000040_list where
a m factors ps@(p:ps')
| m == 1 = factors
| m `mod` p == 0 = a (m `div` p) (p : factors) ps
| otherwise = a m factors ps'
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CROSSREFS
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A001414 gives row sums (for n > 1).
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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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