Numbers n such that phi((prime(n)+1)/2)=sigma(n).

Terms

a(0) =31a(1) =51a(2) =77a(3) =87a(4) =158a(5) =184a(6) =297a(7) =308a(8) =573a(9) =621a(10) =766a(11) =786a(12) =799a(13) =826a(14) =1167a(15) =1330a(16) =1946a(17) =2030a(18) =2280a(19) =3058a(20) =3213a(21) =5015a(22) =5093a(23) =5271a(24) =5374a(25) =8307a(26) =8813a(27) =9730a(28) =10364a(29) =10557