Third differences of A129983.

Terms

a(0) =1a(1) =2a(2) =4a(3) =8a(4) =17a(5) =37a(6) =81a(7) =177a(8) =386a(9) =842a(10) =1841a(11) =4039a(12) =8893a(13) =19645a(14) =43522a(15) =96664a(16) =215181a(17) =479997a(18) =1072741a(19) =2401621a(20) =5385186a(21) =12092582a(22) =27189309a(23) =61204175a(24) =137916217a(25) =311066617a(26) =702185890a(27) =1586252780a(28) =3585742513a(29) =8110367333