Numbers k such that 2*7^k + 3 is prime.

Terms

a(0) =0a(1) =1a(2) =2a(3) =5a(4) =11a(5) =30a(6) =57a(7) =78a(8) =91a(9) =390a(10) =462a(11) =667a(12) =1214a(13) =1811a(14) =2054a(15) =2937a(16) =3055a(17) =8518a(18) =10665a(19) =25430a(20) =45910