OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
EXAMPLE
6 is a term because prime[6]=13 and concatenation of 13 and 1 is prime.
MATHEMATICA
cpfdQ[n_]:=Module[{p=Prime[n]}, PrimeQ[10p+IntegerDigits[p][[1]]]]; Select[ Range[ 400], cpfdQ] (* Harvey P. Dale, Apr 06 2017 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Zak Seidov, Jun 29 2003
STATUS
approved