The number of binary self numbers not exceeding 2^n.

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =5a(5) =10a(6) =18a(7) =34a(8) =67a(9) =131a(10) =261a(11) =520a(12) =1037a(13) =2073a(14) =4143a(15) =8283a(16) =16562a(17) =33121a(18) =66237a(19) =132471a(20) =264938a(21) =529870a(22) =1059740a(23) =2119473a(24) =4238941a(25) =8477878a(26) =16955748a(27) =33911492a(28) =67822978a(29) =135645949