Number of decimal digits in n-th Mersenne prime.

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =4a(5) =6a(6) =6a(7) =10a(8) =19a(9) =27a(10) =33a(11) =39a(12) =157a(13) =183a(14) =386a(15) =664a(16) =687a(17) =969a(18) =1281a(19) =1332a(20) =2917a(21) =2993a(22) =3376a(23) =6002a(24) =6533a(25) =6987a(26) =13395a(27) =25962a(28) =33265a(29) =39751