OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
MATHEMATICA
Select[Range[3000], PrimeOmega[#]==2&&SquareFreeQ[#]&&SquareFreeQ[#+1]&&PrimeQ[#+2]&] (* Harvey P. Dale, Jan 20 2020 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Giovanni Teofilatto, Nov 01 2008
EXTENSIONS
Definition corrected and more terms supplied by R. J. Mathar, Nov 02 2008
STATUS
approved