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A125666
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Table read by antidiagonals: n-th row of table consists of the positive integers divisible by exactly n distinct primes.
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15
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2, 6, 3, 30, 10, 4, 210, 42, 12, 5, 2310, 330, 60, 14, 7, 30030, 2730, 390, 66, 15, 8, 510510, 39270, 3570, 420, 70, 18, 9, 9699690, 570570, 43890, 3990, 462, 78, 20, 11, 223092870, 11741730, 690690, 46410, 4290, 510, 84, 21, 13, 6469693230, 281291010
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OFFSET
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1,1
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COMMENTS
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Concatenated sequence is a permutation of the integers >= 2.
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LINKS
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EXAMPLE
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Table begins:
2,3,4,5,7,8,...
6,10,12,14,15,...
30,42,60,...
210,330,...
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MATHEMATICA
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f[n_, m_] := f[n, m] = Block[{c = m, k = If[m == 1, Product[Prime[i], {i, n}], f[n, m - 1] + 1]}, While[Length@FactorInteger[k] != n, k++ ]; k]; Table[f[d - m + 1, m], {d, 10}, {m, d}] // Flatten (* Ray Chandler, Feb 08 2007 *)
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CROSSREFS
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Cf. A001221, A002110 (col 1), A246655 (row 1), A007774 (row 2), A033992 (row 3), A033993 (row 4), A051270 (row 5), A074969 (row 6), A176655 (row 7), A348072 (row 8), A348073 (row 9), A073329 (diag), compare to A048692.
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KEYWORD
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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