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A124309 5-almost primes indexed by primes. 5

%I

%S 48,72,108,120,180,208,270,280,368,420,450,520,592,612,660,700,760,

%T 828,920,952,976,1032,1064,1128,1242,1288,1323,1372,1380,1428,1575,

%U 1624,1674,1700,1752,1768,1880,1976,2028,2096,2178,2196,2312,2328,2384,2394,2475

%N 5-almost primes indexed by primes.

%H Charles R Greathouse IV, <a href="/A124309/b124309.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = 5almostprime(prime(n)) = A014614(A000040(n)).

%e a(1) = 5almostprime(prime(1)) = 5almostprime(2) = 48 = 2^4 * 3.

%e a(2) = 5almostprime(prime(2)) = 5almostprime(3) = 72 = 2^3 * 3^2.

%e a(3) = 5almostprime(prime(3)) = 5almostprime(5) = 108 = 2^2 * 3^3.

%o (PARI) list(lim)=my(v=List(),u=v); forprime(p=2,lim\16, forprime(q=2,min(lim\(8*p),p), forprime(r=2,min(lim\(4*p*q),q), forprime(s=2,min(lim\(2*p*q*r),r), forprime(t=2,min(lim\(p*q*r*s),s), listput(v,p*q*r*s*t)))))); v=Set(v); forprime(p=2,#v, listput(u,v[p])); v=0; Vec(u) \\ _Charles R Greathouse IV_, Feb 10 2017

%Y Cf. A124308 Primes indexed by 5-almost primes. A124310 prime(5almostprime(n)) - 5almostprime(prime(n)). 4-almost primes indexed by primes = A124283. prime(4almostprime(n)) - 4almostprime(prime(n)) = A124284. Primes indexed by 3-almost primes = A124268. 3-almost primes indexed by primes = A124269. prime(3almostprime(n)) - 3almostprime(prime(n)) = A124270. See also A106349 Primes indexed by semiprimes. See also A106350 Semiprimes indexed by primes. See also A122824 Prime(semiprime(n)) - semiprime(prime(n)). Commutator [A000040, A001358] at n.

%Y Cf. A000040, A014614, A114405, A114415, A124282-A124284, A124309.

%K easy,nonn,less

%O 1,1

%A _Jonathan Vos Post_, Oct 25 2006

%E a(16)-a(47) from _Giovanni Resta_, Jun 13 2016

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Last modified December 14 09:41 EST 2019. Contains 329979 sequences. (Running on oeis4.)