Numbers k such that sigma(k) - 2k is prime.

Terms

a(0) =18a(1) =20a(2) =36a(3) =100a(4) =104a(5) =196a(6) =324a(7) =392a(8) =464a(9) =576a(10) =650a(11) =784a(12) =800a(13) =900a(14) =968a(15) =1352a(16) =1936a(17) =1952a(18) =2450a(19) =2500a(20) =3136a(21) =4356a(22) =4624a(23) =5184a(24) =6050a(25) =6400a(26) =9216a(27) =10000a(28) =10404a(29) =10816