OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
EXAMPLE
37 is a prime which, concatenated with 37+2=39, gives 3739, a prime; so 37 belongs to the sequence.
MATHEMATICA
a = {}; For[i = 1, i <= 10^3, i++, p = Prime[i]; If[PrimeQ[ToExpression[ToString[p] <> ToString[p + 2]]], a = Append[a, p]]]; a
conQ[n_]:=PrimeQ[FromDigits[Join[IntegerDigits[n], IntegerDigits[n+2]]]]; Select[Prime[Range[500]], conQ] (* Harvey P. Dale, May 28 2014 *)
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Joseph L. Pe, Dec 11 2002
STATUS
approved