Spiral sieve using Fibonacci numbers.

Terms

a(0) =1a(1) =3a(2) =4a(3) =6a(4) =9a(5) =13a(6) =21a(7) =28a(8) =59a(9) =93a(10) =122a(11) =249a(12) =385a(13) =592a(14) =999a(15) =1525a(16) =2518a(17) =4141a(18) =6849a(19) =10896a(20) =17935a(21) =28805a(22) =46514a(23) =74581a(24) =121513a(25) =196968a(26) =317255a(27) =515385a(28) =833274a(29) =1347253