A360739 Semiprimes of the form k^2 + 2.

6, 38, 51, 123, 146, 291, 326, 731, 843, 1227, 1371, 1766, 1851, 2306, 2603, 2811, 2918, 3027, 3602, 4227, 4358, 4763, 5186, 5331, 5627, 6243, 6891, 7058, 7571, 8102, 8651, 9411, 13227, 14163, 15627, 17426, 17691, 18227, 18771, 19883, 20738, 22502, 23411, 24027

Offset

1,1

Comments

A242330 gives the corresponding values of k.

Links

Table of n, a(n) for n=1..44.

Formula

a(n) = A242330(n)^2 + 2.

Example

123 is a term because 11^2 + 2 = 123 = 3*41.

Mathematica

Select[Range[0, 200]^2 + 2, PrimeOmega[#] == 2 &] (* Amiram Eldar, Feb 18 2023 *)

Crossrefs

Cf. A001358, A059100, A085722, A144255, A242330.

Sequence in context: A039293 A055713 A216384 * A352305 A060454 A060452

Adjacent sequences: A360736 A360737 A360738 * A360740 A360741 A360742

Keyword

nonn,easy

Author

Elmo R. Oliveira, Feb 18 2023

Status

approved