A trisection of A121653; a(n) = A121653(3*n+1) = A121652(3*n+1)^(1/3).

Terms

a(0) =1a(1) =2a(2) =6a(3) =19a(4) =67a(5) =243a(6) =895a(7) =3366a(8) =12687a(9) =47893a(10) =181457a(11) =687963a(12) =2608418a(13) =9980210a(14) =38267955a(15) =146847036a(16) =566931450a(17) =2192350203a(18) =8483412214a(19) =32931060365a(20) =127961086743a(21) =497417231082