Let p = prime(sigma(n)) and q = prime(phi(n)), then p is in the sequence if p-q = 6.

Terms

a(0) =13a(1) =19a(2) =43a(3) =113a(4) =463a(5) =619a(6) =863a(7) =1789a(8) =2273a(9) =2383a(10) =4519a(11) =4789a(12) =4937a(13) =5443a(14) =5507a(15) =5653a(16) =8237a(17) =10459a(18) =13007a(19) =13697a(20) =16063a(21) =16453a(22) =17389a(23) =18313a(24) =18919a(25) =20903a(26) =21193a(27) =21319a(28) =21383a(29) =23567