Last odd terms from generation 2 onwards.

Terms

a(0) =7a(1) =23a(2) =67a(3) =179a(4) =453a(5) =1109a(6) =2653a(7) =6231a(8) =14409a(9) =32877a(10) =74137a(11) =165429a(12) =365691a(13) =801747a(14) =1745331a(15) =3776605a(16) =8130401a(17) =17427659a(18) =37217597a(19) =79224121a(20) =168170537a(21) =356107787a(22) =752453861a(23) =1586875049a(24) =3340696135a(25) =7021048691a(26) =14731810645