Numbers that are a product of distinct Mersenne primes (elements of A000668).

Terms

a(0) =1a(1) =3a(2) =7a(3) =21a(4) =31a(5) =93a(6) =127a(7) =217a(8) =381a(9) =651a(10) =889a(11) =2667a(12) =3937a(13) =8191a(14) =11811a(15) =24573a(16) =27559a(17) =57337a(18) =82677a(19) =131071a(20) =172011a(21) =253921a(22) =393213a(23) =524287a(24) =761763a(25) =917497a(26) =1040257a(27) =1572861a(28) =1777447a(29) =2752491