Numbers k such that sigma(k) + tau(k) is a prime.

Terms

a(0) =1a(1) =2a(2) =8a(3) =128a(4) =162a(5) =512a(6) =32768a(7) =41472a(8) =101250a(9) =125000a(10) =1414562a(11) =3748322a(12) =5120000a(13) =6837602a(14) =8000000a(15) =13530402a(16) =24234722a(17) =35701250a(18) =66724352a(19) =75031250a(20) =78125000a(21) =86093442a(22) =91125000a(23) =171532242a(24) =177058562a(25) =226759808a(26) =233971712a(27) =617831552a(28) =664301250a(29) =686128968