Fifth spoke of a hexagonal spiral.

Terms

a(0) =1a(1) =6a(2) =17a(3) =34a(4) =57a(5) =86a(6) =121a(7) =162a(8) =209a(9) =262a(10) =321a(11) =386a(12) =457a(13) =534a(14) =617a(15) =706a(16) =801a(17) =902a(18) =1009a(19) =1122a(20) =1241a(21) =1366a(22) =1497a(23) =1634a(24) =1777a(25) =1926a(26) =2081a(27) =2242a(28) =2409a(29) =2582