Number of 3-element nondividing subsets of {1, 2, ..., n}.

Terms

a(0) =1a(1) =2a(2) =6a(3) =12a(4) =22a(5) =31a(6) =49a(7) =70a(8) =99a(9) =128a(10) =176a(11) =216a(12) =284a(13) =343a(14) =423a(15) =515a(16) =633a(17) =722a(18) =860a(19) =1007a(20) =1173a(21) =1333a(22) =1552a(23) =1729a(24) =1989a(25) =2223a(26) =2502a(27) =2809a(28) =3138a(29) =3416