a(n) = n-th prime modulo 4.

Terms

a(0) =2a(1) =3a(2) =1a(3) =3a(4) =3a(5) =1a(6) =1a(7) =3a(8) =3a(9) =1a(10) =3a(11) =1a(12) =1a(13) =3a(14) =3a(15) =1a(16) =3a(17) =1a(18) =3a(19) =3a(20) =1a(21) =3a(22) =3a(23) =1a(24) =1a(25) =1a(26) =3a(27) =3a(28) =1a(29) =1