Catapolyoctagons (see Cyvin et al. for precise definition).

Terms

a(0) =1a(1) =1a(2) =3a(3) =9a(4) =39a(5) =169a(6) =819a(7) =3969a(8) =19719a(9) =97969a(10) =489219a(11) =2442969a(12) =12211719a(13) =61042969a(14) =305199219a(15) =1525917969a(16) =7629511719a(17) =38147167969a(18) =190735449219a(19) =953675292969