Leading diagonal of array in A100461.

Terms

a(0) =1a(1) =1a(2) =1a(3) =3a(4) =7a(5) =25a(6) =49a(7) =109a(8) =229a(9) =481a(10) =1003a(11) =2019a(12) =4051a(13) =8143a(14) =16309a(15) =32683a(16) =65439a(17) =131007a(18) =262081a(19) =524187a(20) =1048423a(21) =2097027a(22) =4194147a(23) =8388481a(24) =16777039a(25) =33554269a(26) =67108699a(27) =134217529a(28) =268435227a(29) =536870713