

A074969


Numbers with six distinct prime divisors.


7



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
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OFFSET

1,1


COMMENTS

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 kalmost primes are the more general class than our dalmost primes with d=k. In the sequence, dalmost 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.


LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000


FORMULA

{n : A001221(n) = 6} .  R. J. Mathar, Jul 07 2012


EXAMPLE

60060 is in the sequence because 60060 = 2^2*3*5*7*11*13 with six distinct prime divisors 2, 3, 5, 7, 11, 13; 87780 is in the sequence because 87780 = 2^2*3*5*7*11*19 with six distinct prime divisors 2, 3, 5, 7, 11, 19.


MATHEMATICA

Select[Range[0, 5*8! ], Length[FactorInteger[ # ]]==6&] (* Vladimir Joseph Stephan Orlovsky, Apr 22 2010 *)


PROG

(PARI) is(n)=omega(n)==6 \\ Charles R Greathouse IV, Jun 19 2016


CROSSREFS

Cf. A067885, A001358, A014612, A014613, A014614, A051270, A033993, A033992, A000040.
Sequence in context: A106771 A184502 A285655 * A066765 A067885 A285615
Adjacent sequences: A074966 A074967 A074968 * A074970 A074971 A074972


KEYWORD

nonn


AUTHOR

Zak Seidov, Oct 04 2002


STATUS

approved



