Oblong numbers of the form (k-1)*k where k is the product of an odd number of distinct primes.

Terms

a(0) =2a(1) =6a(2) =20a(3) =42a(4) =110a(5) =156a(6) =272a(7) =342a(8) =506a(9) =812a(10) =870a(11) =930a(12) =1332a(13) =1640a(14) =1722a(15) =1806a(16) =2162a(17) =2756a(18) =3422a(19) =3660a(20) =4290a(21) =4422a(22) =4830a(23) =4970a(24) =5256a(25) =6006a(26) =6162a(27) =6806a(28) =7832a(29) =9312