A177088 Numbers n such that n^5-n^3-2*n^2+1 is semiprime.

5, 7, 9, 11, 13, 14, 17, 19, 20, 26, 27, 29, 31, 34, 40, 41, 42, 43, 49, 50, 51, 53, 54, 56, 61, 62, 63, 64, 66, 68, 71, 72, 74, 76, 88, 89, 92, 95, 97, 105, 107, 108, 109, 110, 113, 115, 116, 117, 119, 125, 127, 128, 130, 133, 134, 135, 136, 138, 139, 142, 144, 145

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Mathematica

Select[Range[300], PrimeOmega[#^5 - #^3 - 2 #^2 + 1]==2&] (* Vincenzo Librandi, May 14 2014 *)

Prog

(Magma) IsSemiprime:=func<i | &+[d[2]: d in Factorization(i)] eq 2>; [n: n in [2..200] | IsSemiprime(s) where s is n^5-n^3-2*n^2+1]; // Vincenzo Librandi, May 14 2014

Crossrefs

Cf. A177075, A177076.

Sequence in context: A279244 A325797 A128163 * A362486 A168146 A343064

Adjacent sequences: A177085 A177086 A177087 * A177089 A177090 A177091

Keyword

nonn,easy,less

Author

Vincenzo Librandi, Jun 05 2010

Status

approved