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

Terms

a(0) =1a(1) =1a(2) =4a(3) =13a(4) =41a(5) =150a(6) =568a(7) =2115a(8) =7974a(9) =30307a(10) =115063a(11) =436831a(12) =1659809a(13) =6306619a(14) =24210855a(15) =93152526a(16) =357925365a(17) =1384070472a(18) =5365825156a(19) =20791117843a(20) =80784911668a(21) =314369613909