a(n) = integer nearest n*Pi.

Terms

a(0) =0a(1) =3a(2) =6a(3) =9a(4) =13a(5) =16a(6) =19a(7) =22a(8) =25a(9) =28a(10) =31a(11) =35a(12) =38a(13) =41a(14) =44a(15) =47a(16) =50a(17) =53a(18) =57a(19) =60a(20) =63a(21) =66a(22) =69a(23) =72a(24) =75a(25) =79a(26) =82a(27) =85a(28) =88a(29) =91