a(1)=3; a(n)=first odd number greater than a(n-1) such that 2*a(n)-1 is prime and a(i)+a(n)-1 is prime for all 1<=i<=n-1.
A120403
a(1)=3; a(n)=first odd number greater than a(n-1) such that 2*a(n)-1 is prime and a(i)+a(n)-1 is prime for all 1<=i<=n-1.
Terms
- a(0) =3a(1) =9a(2) =15a(3) =45a(4) =225a(5) =639a(6) =1275a(7) =4005a(8) =675405a(9) =2203959a(10) =3075159a(11) =6195234165a(12) =77989711185
External references
- oeis: A120403