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Search: id:A125666
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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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+0
1
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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
(list; table; graph; listen)
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OFFSET
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1,1
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COMMENT
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Concatenated sequence is a permutation of the integers >= 2.
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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(*Chandler*)
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CROSSREFS
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Cf. A001221, A002110 (col 1), A000961 (row 1), A007774 (row 2), A033992 (row 3), A033993 (row 4), A051270 (row 5), A074969 (row 6), A073329 (diag), compare to A048692.
Sequence in context: A050125 A008306 A144362 this_sequence A111678 A101819 A128192
Adjacent sequences: A125663 A125664 A125665 this_sequence A125667 A125668 A125669
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KEYWORD
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nonn,tabl
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AUTHOR
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Leroy Quet (q1qq2qqq3qqqq(AT)yahoo.com), Jan 29 2007
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EXTENSIONS
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Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Feb 08 2007
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