Number of composite numbers between exponents of successive Mersenne primes.

Terms

a(0) =0a(1) =1a(2) =1a(3) =4a(4) =3a(5) =1a(6) =9a(7) =23a(8) =22a(9) =14a(10) =17a(11) =327a(12) =73a(13) =576a(14) =803a(15) =67a(16) =820a(17) =908a(18) =151a(19) =4672a(20) =222a(21) =1141a(22) =7827a(23) =1583a(24) =1352a(25) =19255a(26) =37986a(27) =22155a(28) =19704a(29) =77081