1,1

Table of n, a(n) for n=1..37.

The prime factors of 51 are 3 and 17 and their concatenation 317 is prime, so 51 belongs to the sequence.

Sequence in context: A039115 A285964 A198045 * A152854 A341763 A201144

Adjacent sequences: A068995 A068996 A068997 * A068999 A069000 A069001

base,easy,nonn

Joseph L. Pe, Mar 16 2002

approved