Number of lesser twin primes (A001359) in range ]2^n, 2^(n+1)].

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =2a(5) =3a(6) =7a(7) =7a(8) =12a(9) =26a(10) =45a(11) =70a(12) =113a(13) =215a(14) =355a(15) =666a(16) =1153a(17) =2071a(18) =3785a(19) =6965a(20) =12495a(21) =22643a(22) =41608a(23) =76371a(24) =140944a(25) =261752a(26) =484968a(27) =904799a(28) =1689477a(29) =3160113