Least k>1 such that p^k - p^(k-1) - 1 is prime for p = prime(n).

Terms

a(0) =3a(1) =2a(2) =2a(3) =2a(4) =2a(5) =3a(6) =2a(7) =7a(8) =56a(9) =2a(10) =2a(11) =8a(12) =8a(13) =8a(14) =2a(15) =4a(16) =4a(17) =2a(18) =2a(19) =2a(20) =9a(21) =3a(22) =21496a(23) =26a(24) =2a(25) =2a(26) =4a(27) =38a(28) =7a(29) =286644