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A124945 Numbers k such that k and k+10 are 10-almost primes.

%I A124945 #12 Dec 14 2024 11:00:46
%S A124945 506240,789750,1325312,1567350,1761750,1944800,2450240,2579840,
%T A124945 3004928,3013686,3093750,3153654,3713526,3844736,3906240,4024566,
%U A124945 4394240,5244416,5402240,5431040,6208640,6310710,6932790,7053750,7352694,7585974,8005878,8043776,8099190
%N A124945 Numbers k such that k and k+10 are 10-almost primes.
%C A124945 First term 506240 = A098515(10).
%H A124945 Charles R Greathouse IV, <a href="/A124945/b124945.txt">Table of n, a(n) for n = 1..10000</a>
%e A124945 506240=2^7*5*7*113, 506250=2*3^4*5^5;
%e A124945 789750=2*3^5*5^3*13, 789760=2^8*5*617;
%e A124945 1325312=2^8*31*167, 1325322=2*3^8*101;
%e A124945 1567350=2*3^6*5^2*43, 1567360=2^7*5*31*79.
%t A124945 Select[Range[10^7],PrimeOmega[#]==PrimeOmega[#+10]==10&] (* _James C. McMahon_, Dec 14 2024 *)
%o A124945 (PARI) isok(n) = (bigomega(n) == 10) && (bigomega(n+10) == 10); \\ _Michel Marcus_, Oct 11 2013
%o A124945 (PARI) P=prod(i=1,25,prime(i))^10; v=List(); for(n=1,1e6, g1=gcd(n,P); o1=bigomega(g1); if(o1<5,next); g2=gcd(n+10,P); o2=bigomega(g2); if(o2>=5 && o1+bigomega(n/g1)==10 && o2+bigomega((n+10)/g2)==10, listput(v,n))); Vec(v) \\ _Charles R Greathouse IV_, Oct 11 2013
%Y A124945 Cf. A098515, A124940, A124941, A124942.
%K A124945 nonn
%O A124945 1,1
%A A124945 _Zak Seidov_, Nov 13 2006
%E A124945 More terms from _Michel Marcus_, Oct 11 2013