Numbers k such that (68*10^k - 11)/3 is prime.

Terms

a(0) =0a(1) =1a(2) =4a(3) =6a(4) =9a(5) =20a(6) =57a(7) =64a(8) =88a(9) =196a(10) =265a(11) =421a(12) =620a(13) =654a(14) =729a(15) =1587a(16) =4863a(17) =6628a(18) =12358a(19) =23773a(20) =68798a(21) =119931