Semiprimes that are a product of distinct Mersenne primes.

Terms

a(0) =21a(1) =93a(2) =217a(3) =381a(4) =889a(5) =3937a(6) =24573a(7) =57337a(8) =253921a(9) =393213a(10) =917497a(11) =1040257a(12) =1572861a(13) =3670009a(14) =4063201a(15) =16252897a(16) =16646017a(17) =66584449a(18) =1073602561a(19) =4294434817a(20) =6442450941a(21) =15032385529a(22) =66571993057a(23) =68718821377a(24) =272730423169