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A046387
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Products of 5 distinct primes.
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20
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2310, 2730, 3570, 3990, 4290, 4830, 5610, 6006, 6090, 6270, 6510, 6630, 7410, 7590, 7770, 7854, 8610, 8778, 8970, 9030, 9282, 9570, 9690, 9870, 10010, 10230, 10374, 10626, 11130, 11310, 11730, 12090, 12210, 12390, 12558, 12810, 13090, 13110
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OFFSET
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1,1
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COMMENTS
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Subsequence of A051270. 4620 = 2^2*3*5*7*11 is in A051270 but not in here, for example. - R. J. Mathar, Nov 10 2014
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LINKS
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T. D. Noe, Table of n, a(n) for n = 1..10000
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EXAMPLE
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a(1) = 2310 = 2 * 3 * 5 * 7 * 11 = A002110(5) = 5#.
a(2) = 2730 = 2 * 3 * 5 * 7 * 13.
a(3) = 3570 = 2 * 3 * 5 * 7 * 17.
a(10) = 6006 = 2 * 3 * 7 * 11 * 13.
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MAPLE
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A046387 := proc(n)
option remember;
local a;
if n = 1 then
2*3*5*7*11 ;
else
for a from procname(n-1)+1 do
if A001221(a)= 5 and issqrfree(a) then
return a;
end if;
end do:
end if;
end proc: # R. J. Mathar, Oct 13 2019
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MATHEMATICA
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f5Q[n_]:=Last/@FactorInteger[n]=={1, 1, 1, 1, 1}; lst={}; Do[If[f5Q[n], AppendTo[lst, n]], {n, 8!}]; lst (* Vladimir Joseph Stephan Orlovsky, Aug 26 2008 *)
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PROG
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(PARI) is(n)=factor(n)[, 2]==[1, 1, 1, 1, 1]~ \\ Charles R Greathouse IV, Sep 17 2015
(PARI) is(n)= omega(n)==5 && bigomega(n)==5 \\ Hugo Pfoertner, Dec 18 2018
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CROSSREFS
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Cf. A067885 (product of 6 distinct primes).
Cf. A000040, A000961, A001221, A005117, A000977, A002110, A006881, A007304, A007774, A033992, A033993, A046386.
Cf. A014614, A046403, A051270.
Sequence in context: A285487 A285744 A051270 * A136154 A258360 A076252
Adjacent sequences: A046384 A046385 A046386 * A046388 A046389 A046390
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KEYWORD
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easy,nonn
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AUTHOR
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Patrick De Geest, Jun 15 1998
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EXTENSIONS
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Entry revised by N. J. A. Sloane, Apr 10 2006
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STATUS
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approved
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