A259189 Semiprimes of the form n^3 + 2.

10, 218, 514, 731, 1333, 2199, 2746, 3377, 4915, 5834, 6861, 8002, 9263, 12169, 15627, 29793, 35939, 42877, 54874, 59321, 68923, 117651, 125002, 132653, 148879, 185195, 205381, 314434, 405226, 421877, 474554, 531443, 592706, 658505, 704971

Offset

1,1

Comments

Intersection of A001358 and A084380. - Michel Marcus, Jun 20 2015

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

No term in A040034 divides any term in this sequence.

Links

Jon E. Schoenfield, Table of n, a(n) for n = 1..10000

Mathematica

Select[Range[100]^3 + 2, PrimeOmega[#] == 2 &] (* Alonso del Arte, Jun 20 2015 *)

Prog

(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];
(Perl) use ntheory ":all"; my @sp = grep { scalar(factor($_))==2 } map { $_**3+2 } 1..100; say "@sp"; # Dana Jacobsen, Sep 07 2015
(PARI) is(n)=bigomega(n^3 + 2)==2 \\ Anders Hellström, Sep 07 2015

Crossrefs

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

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

Sequence in context: A305107 A374794 A294850 * A326208 A007698 A007699

Adjacent sequences: A259186 A259187 A259188 * A259190 A259191 A259192

Keyword

nonn

Author

Morris Neene, Jun 20 2015

Status

approved