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A080671 Numbers having divisors 2 or 3 or 5. 5

%I #28 Nov 11 2023 03:38:24

%S 2,3,4,5,6,8,9,10,12,14,15,16,18,20,21,22,24,25,26,27,28,30,32,33,34,

%T 35,36,38,39,40,42,44,45,46,48,50,51,52,54,55,56,57,58,60,62,63,64,65,

%U 66,68,69,70,72,74,75,76,78,80,81,82,84,85,86,87,88,90,92,93,94,95,96,98

%N Numbers having divisors 2 or 3 or 5.

%C Complement of A007775. - _Gary Detlefs_, Oct 06 2013

%C The asymptotic density of this sequence is 11/15. - _Amiram Eldar_, Dec 07 2020

%H N. J. A. Sloane, <a href="/A080671/b080671.txt">Table of n, a(n) for n = 1..10000</a>

%H <a href="/index/Rec#order_22">Index entries for linear recurrences with constant coefficients</a>, signature (2,-2,2,-2,2,-2,2,-2,2,-2,2,-2,2,-2,2,-2,2,-2,2,-2,2,-1).

%F a(n+22) = a(n) + 30. - _Gary Detlefs_, Oct 06 2013

%p A080671 := proc(n) local s; option remember;

%p s:=[2, 3, 4, 5, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 22, 24, 25, 26, 27, 28, 30];

%p if n <= 22 then s[n] else 30 + A080671(n-22); fi; end proc; # _N. J. A. Sloane_, Sep 01 2022

%t Select[Range[98], Mod[#, 2]*Mod[#, 3]*Mod[#, 5] == 0 &] (* _T. D. Noe_, Oct 07 2013 *)

%o (PARI) div235(n) = { for(x=1,n, if(gcd(x,30)<>1,print1(x", ")) ) }

%Y Cf. A007775.

%K easy,nonn

%O 1,1

%A _Cino Hilliard_, Mar 02 2003

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Last modified May 9 12:21 EDT 2024. Contains 372350 sequences. (Running on oeis4.)