Spiral sieve using Fibonacci numbers.

Terms

a(0) =1a(1) =4a(2) =6a(3) =7a(4) =9a(5) =13a(6) =21a(7) =46a(8) =71a(9) =109a(10) =168a(11) =265a(12) =417a(13) =562a(14) =1051a(15) =1677a(16) =2484a(17) =4053a(18) =6601a(19) =10738a(20) =17979a(21) =28997a(22) =46800a(23) =75573a(24) =120697a(25) =197306a(26) =318939a(27) =515665a(28) =830216a(29) =1343949