First differences of A213709.

Terms

a(0) =0a(1) =1a(2) =1a(3) =2a(4) =4a(5) =8a(6) =13a(7) =24a(8) =44a(9) =81a(10) =151a(11) =284a(12) =536a(13) =1012a(14) =1910a(15) =3606a(16) =6818a(17) =12922a(18) =24561a(19) =46821a(20) =89509a(21) =171580a(22) =329760a(23) =635357a(24) =1227025a(25) =2374558a(26) =4602962a(27) =8933547a(28) =17352195a(29) =33718878