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A176167 First of a triple of consecutive integers, each the product of 4 distinct primes. 6

%I #20 Jul 18 2023 23:26:02

%S 203433,214489,225069,258013,294593,313053,315721,352885,389389,

%T 409353,418845,421629,452353,464385,478905,485133,500905,508045,

%U 508989,526029,528409,538745,542269,542793,548301,556869,559689,569065,571233,579885

%N First of a triple of consecutive integers, each the product of 4 distinct primes.

%C A subsequence of A242607 and A016813. - _M. F. Hasler_, May 19 2014

%H Zak Seidov, <a href="/A176167/b176167.txt">Table of n, a(n) for n = 1..1000</a>

%e 203433 is a term: 203433 = 3*19*43*83, 203434 = 2*7*11*1321, 203435 = 5*23*29*61.

%t f1[n_]:=Last/@FactorInteger[n]=={1,1,1,1};f2[n_]:=Max[Last/@FactorInteger[n]];lst={};Do[If[f1[n]&&f1[n+1]&&f1[n+2],AppendTo[lst,n]],{n,5*8!,7*9!}];lst

%o (PARI) forstep(n=1+10^5,10^7,4, for(k=n,n+2,issquarefree(k)||next(2)); for(k=n,n+2,omega(k)==4||next(2));print1((n)",")) \\ _M. F. Hasler_, May 19 2014

%Y Cf. A039833, A066509, A192203. Subsequence of A140078 and of A318896.

%K nonn

%O 1,1

%A _Vladimir Joseph Stephan Orlovsky_, Apr 10 2010

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Last modified April 25 12:28 EDT 2024. Contains 371969 sequences. (Running on oeis4.)