The 180-degree spoke (or ray) of a hexagonal spiral of Ulam.

Terms

a(0) =1a(1) =18a(2) =59a(3) =124a(4) =213a(5) =326a(6) =463a(7) =624a(8) =809a(9) =1018a(10) =1251a(11) =1508a(12) =1789a(13) =2094a(14) =2423a(15) =2776a(16) =3153a(17) =3554a(18) =3979a(19) =4428a(20) =4901a(21) =5398a(22) =5919a(23) =6464a(24) =7033a(25) =7626a(26) =8243a(27) =8884a(28) =9549a(29) =10238