Octagonal numbers with prime indices.

Terms

a(0) =8a(1) =21a(2) =65a(3) =133a(4) =341a(5) =481a(6) =833a(7) =1045a(8) =1541a(9) =2465a(10) =2821a(11) =4033a(12) =4961a(13) =5461a(14) =6533a(15) =8321a(16) =10325a(17) =11041a(18) =13333a(19) =14981a(20) =15841a(21) =18565a(22) =20501a(23) =23585a(24) =28033a(25) =30401a(26) =31621a(27) =34133a(28) =35425a(29) =38081