Covering numbers C(n,5,2).

Terms

a(0) =1a(1) =3a(2) =3a(3) =4a(4) =5a(5) =6a(6) =7a(7) =9a(8) =10a(9) =12a(10) =13a(11) =15a(12) =16a(13) =18a(14) =19a(15) =21a(16) =21a(17) =27a(18) =28a(19) =30a(20) =30a(21) =37a(22) =38a(23) =40