Number of quadratic residues mod n for some n (A000224 sorted and duplicates removed).

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =6a(5) =7a(6) =8a(7) =9a(8) =10a(9) =11a(10) =12a(11) =14a(12) =15a(13) =16a(14) =18a(15) =19a(16) =20a(17) =21a(18) =22a(19) =23a(20) =24a(21) =27a(22) =28a(23) =30a(24) =31a(25) =32a(26) =33a(27) =34a(28) =36a(29) =37