OFFSET
1,1
COMMENTS
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
EXAMPLE
121 is in the sequence because 10201, 11211, 12221, 13231, 14241, 15251, 16261, 17271, 18281, 19291 are all composite.
MATHEMATICA
Select[Select[Range[11, 900, 2], PrimeOmega[#]==2&], AllTrue[Table[ FromDigits[ Riffle[ IntegerDigits[#], n]], {n, 0, 9}], CompositeQ]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Mar 07 2018 *)
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Jonathan Vos Post, Oct 18 2007
EXTENSIONS
More terms from R. J. Mathar, Oct 22 2007
STATUS
approved