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A085987
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Product of exactly four primes, three of which are distinct.
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30
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60, 84, 90, 126, 132, 140, 150, 156, 198, 204, 220, 228, 234, 260, 276, 294, 306, 308, 315, 340, 342, 348, 350, 364, 372, 380, 414, 444, 460, 476, 490, 492, 495, 516, 522, 525, 532, 550, 558, 564, 572, 580, 585, 620, 636, 644, 650, 666, 693, 708, 726
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| A014613 is completely determined by A030514, A065036, A085986, A085987 and A046386 since p(4) = 5. (cf. A000041). More generally, the first term of sequences which completely determine the k-almost primes can be found in A036035 (a resorted version of A025487).
Subsequence of A178212. [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), May 24 2010]
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LINKS
| T. D. Noe, Table of n, a(n) for n = 1..1000
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EXAMPLE
| a(1) = 60 since 60 = 2*2*3*5 and has three distinct prime factors.
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MATHEMATICA
| f[n_]:=Sort[Last/@FactorInteger[n]]=={1, 1, 2}; Select[Range[2000], f] (* From Vladimir Joseph Stephan Orlovsky, May 03 2011 *)
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PROG
| (PARI) list(lim)=my(v=List(), t, x, y, z); forprime(p=2, lim^(1/4), t=lim\p^2; forprime(q=p+1, sqrtint(t), forprime(r=q+1, t\q, x=p^2*q*r; y=p*q^2*r; listput(v, x); if(y<=lim, listput(v, y); z=p*q*r^2; if(z<=lim, listput(v, z)))))); vecsort(Vec(v)) \\ Charles R Greathouse IV, Jul 15 2011
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CROSSREFS
| Cf. A000007, A000040, A001248, A006881, A030078, A054753, A007304, A050997, A046387, A036035, A086974.
Sequence in context: A182855 A009129 A174292 * A086974 A099831 A138604
Adjacent sequences: A085984 A085985 A085986 * A085988 A085989 A085990
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KEYWORD
| nonn
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AUTHOR
| Alford Arnold (Alford1940(AT)aol.com), Jul 08 2003
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EXTENSIONS
| More terms from Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jul 25 2003
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