Semiprimes of form p*q with p < q, such that 2^p - 1 == 0 (mod q).

Terms

a(0) =6a(1) =21a(2) =155a(3) =253a(4) =889a(5) =979a(6) =1081a(7) =6757a(8) =8251a(9) =13861a(10) =18533a(11) =31987a(12) =32047a(13) =34453a(14) =60581a(15) =64261a(16) =73153a(17) =106483a(18) =110497a(19) =114481a(20) =126253a(21) =212111a(22) =212273a(23) =256507a(24) =258121a(25) =325967a(26) =337133a(27) =351541a(28) =371953a(29) =383183