An alternating 2-based sum from prime(n) up to the base of the n-th Mersenne prime.

Terms

a(0) =0a(1) =5a(2) =7a(3) =9a(4) =18a(5) =25a(6) =24a(7) =51a(8) =120a(9) =181a(10) =223a(11) =264a(12) =1243a(13) =1455a(14) =3129a(15) =5430a(16) =5616a(17) =7953a(18) =10534a(19) =10953a(20) =24115a(21) =24736a(22) =27910a(23) =49711a(24) =54109a(25) =57873a(26) =111090a(27) =215449a(28) =276096a(29) =329955