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Search: id:A074969
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| A074969 |
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Numbers with six distinct prime divisors. |
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+0
5
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| 30030, 39270, 43890, 46410, 51870, 53130, 60060, 62790, 66990, 67830, 71610, 72930, 78540, 79170, 81510, 82110, 84630, 85470, 87780, 90090, 91770, 92820, 94710, 98670, 99330, 101010, 102102, 103530, 103740, 106260, 106590, 108570
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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The smallest number with six distinct prime divisors is the product of first six primes, 2*3*5*7*11=30030. The smallest number with seven distinct prime divisors is product of first seven primes, 2*3*5*7*11*13=390390. Note that in A001358 (product of two primes), A014612 (product of three primes), A014613 (product of four primes), A014614 (product of five primes), primes are not necessarily distinct, so k-almost primes are the more general class than our d-almost primes with d=k. In the sequence, d-almost primes with d=6 are considered, see also A051270 (d=5), A033993 (d=4), A033992 (d=3), A007774 (d=2). The case d=1 (or k=1) corresponds to primes A000040.
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EXAMPLE
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60060 is OK because 60060=2^2*3*5*7*11 with six distinct prime divisors 2, 3, 5, 7, 11, 13; 87780 is OK because 87780=2^2*3*5*11*19 with six distinct prime divisors 2, 3, 5, 7, 11, 19.
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CROSSREFS
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Cf. A001358, A014612, A014613, A014614, A051270, A033993, A033992, A000040.
Sequence in context: A056747 A157614 A106771 this_sequence A066765 A067885 A072940
Adjacent sequences: A074966 A074967 A074968 this_sequence A074970 A074971 A074972
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KEYWORD
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nonn
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AUTHOR
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Zak Seidov (zakseidov(AT)yahoo.com), Oct 04 2002
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