a(n) is the least k such that Mersenne-prime(n)*prime(k)# + 1 is prime, where prime(k)# is the k-th primorial.

A098571

a(n) is the least k such that Mersenne-prime(n)*prime(k)# + 1 is prime, where prime(k)# is the k-th primorial.

Terms

    a(0) =1a(1) =2a(2) =6a(3) =6a(4) =16a(5) =5a(6) =3a(7) =4a(8) =5a(9) =33a(10) =29a(11) =24a(12) =31a(13) =124a(14) =290a(15) =103a(16) =370a(17) =186a(18) =4654a(19) =133a(20) =221a(21) =244a(22) =206a(23) =726a(24) =601a(25) =18

External references