A112630 Squares of the form 3S + 4, where S is a semiprime.

16, 49, 121, 169, 289, 361, 961, 1225, 1681, 2401, 3025, 3481, 5041, 7225, 8281, 9025, 11881, 15625, 19321, 25921, 30625, 32041, 32761, 39601, 48841, 55225, 57121, 70225, 72361, 93025, 96721, 101761, 108241

Offset

1,1

Links

Table of n, a(n) for n=1..33.

Mathematica

Select[Select[Range[50000], PrimeOmega[#]==2&]*3+4, IntegerQ[Sqrt[#]]&] (* James C. McMahon, Jun 05 2024 *)

Prog

(PARI) select(issquare, apply(x->3*x+4, select(x->(bigomega(x)==2), [1..100000]))) \\ Michel Marcus, Jun 15 2024

Crossrefs

Subsequence of A000290.

Cf. A001358.

Sequence in context: A016778 A009952 A105823 * A039606 A041498 A264479

Adjacent sequences: A112627 A112628 A112629 * A112631 A112632 A112633

Keyword

nonn

Author

Giovanni Teofilatto, Dec 22 2005

Extensions

Extended beyond 289 by R. J. Mathar, Jun 28 2010

Status

approved