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Semiprimes of the form n^3 + 2.
1

%I #26 Sep 08 2022 08:46:13

%S 10,218,514,731,1333,2199,2746,3377,4915,5834,6861,8002,9263,12169,

%T 15627,29793,35939,42877,54874,59321,68923,117651,125002,132653,

%U 148879,185195,205381,314434,405226,421877,474554,531443,592706,658505,704971

%N Semiprimes of the form n^3 + 2.

%C Intersection of A001358 and A084380. - _Michel Marcus_, Jun 20 2015

%C Since there are no squares of the form n^3 + 2, all semiprimes in this sequence are products of distinct primes.

%C No term in A040034 divides any term in this sequence.

%H Jon E. Schoenfield, <a href="/A259189/b259189.txt">Table of n, a(n) for n = 1..10000</a>

%t Select[Range[100]^3 + 2, PrimeOmega[#] == 2 &] (* _Alonso del Arte_, Jun 20 2015 *)

%o (Magma) IsSP:=func<n|&+[d[2]:d in Factorization(n)]eq 2>;[r:n in [1..1000]|IsSP(r) where r is 2+n^3];

%o (Perl) use ntheory ":all"; my @sp = grep { scalar(factor($_))==2 } map { $_**3+2 } 1..100; say "@sp"; # _Dana Jacobsen_, Sep 07 2015

%o (PARI) is(n)=bigomega(n^3 + 2)==2 \\ _Anders Hellström_, Sep 07 2015

%Y Cf. A001358 (semiprimes), A084380 (n^3+2), A144953 (primes of same form).

%Y Cf. A237040 (similar sequence with n^3+1).

%K nonn

%O 1,1

%A _Morris Neene_, Jun 20 2015