Primes in A068657.

Terms

a(0) =31a(1) =421a(2) =521a(3) =631a(4) =9421a(5) =14731a(6) =15731a(7) =189421a(8) =36189421a(9) =39199421a(10) =492412631a(11) =542713631a(12) =603015731a(13) =7236189421a(14) =7537189421a(15) =97482412631a(16) =99492412631a(17) =102512512631a(18) =107532613631a(19) =114572814731