Sums of two (not necessarily distinct) Mersenne primes (A000668).

Terms

a(0) =6a(1) =10a(2) =14a(3) =34a(4) =38a(5) =62a(6) =130a(7) =134a(8) =158a(9) =254a(10) =8194a(11) =8198a(12) =8222a(13) =8318a(14) =16382a(15) =131074a(16) =131078a(17) =131102a(18) =131198a(19) =139262a(20) =262142a(21) =524290a(22) =524294a(23) =524318a(24) =524414a(25) =532478a(26) =655358a(27) =1048574a(28) =2147483650a(29) =2147483654