A124945 - OEIS

%I #9 Oct 11 2013 21:25:16

%S 506240,789750,1325312,1567350,1761750,1944800,2450240,2579840,

%T 3004928,3013686,3093750,3153654,3713526,3844736,3906240,4024566,

%U 4394240,5244416,5402240,5431040,6208640,6310710,6932790,7053750,7352694,7585974,8005878,8043776,8099190

%N n and n+10 are 10-almost primes.

%C First term 506240 = A098515(10).

%H Charles R Greathouse IV, <a href="/A124945/b124945.txt">Table of n, a(n) for n = 1..10000</a>

%e 506240=2^7*5*7*113, 506250=2*3^4*5^5;

%e 789750=2*3^5*5^3*13, 789760=2^8*5*617;

%e 1325312=2^8*31*167, 1325322=2*3^8*101;

%e 1567350=2*3^6*5^2*43, 1567360=2^7*5*31*79.

%o (PARI) isok(n) = (bigomega(n) == 10) && (bigomega(n+10) == 10); \\ _Michel Marcus_, Oct 11 2013

%o (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 Cf. A098515, A124940, A124941, A124942.

%K nonn

%O 1,1

%A _Zak Seidov_, Nov 13 2006

%E More terms from _Michel Marcus_, Oct 11 2013