Second elementary symmetric function of divisors of n.

Terms

a(0) =0a(1) =2a(2) =3a(3) =14a(4) =5a(5) =47a(6) =7a(7) =70a(8) =39a(9) =97a(10) =11a(11) =287a(12) =13a(13) =163a(14) =158a(15) =310a(16) =17a(17) =533a(18) =19a(19) =609a(20) =262a(21) =343a(22) =23a(23) =1375a(24) =155a(25) =457a(26) =390a(27) =1043a(28) =29a(29) =1942