Numbers n such that sigma(n) + phi(n) is a composite number of the form p^k where p is a prime.

Terms

a(0) =2a(1) =4a(2) =12a(3) =15a(4) =110a(5) =121a(6) =125a(7) =511a(8) =908a(9) =2047a(10) =31269a(11) =58252a(12) =180544a(13) =2275680a(14) =3776877a(15) =4164717a(16) =4835820a(17) =8386433a(18) =8388607a(19) =32284479a(20) =60333777a(21) =82628532a(22) =122016110a(23) =174438012a(24) =238609292a(25) =513528686a(26) =515718093a(27) =919749786a(28) =1043394771a(29) =3851465145