Covering numbers C(n,3,2).

Terms

a(0) =1a(1) =3a(2) =4a(3) =6a(4) =7a(5) =11a(6) =12a(7) =17a(8) =19a(9) =24a(10) =26a(11) =33a(12) =35a(13) =43a(14) =46a(15) =54a(16) =57a(17) =67a(18) =70a(19) =81a(20) =85a(21) =96a(22) =100a(23) =113a(24) =117a(25) =131a(26) =136a(27) =150a(28) =155a(29) =171