Golden Triangle sums: a(n)=a(n-2)+A001654(n) with a(0)=0 and a(1)=1.

Terms

a(0) =0a(1) =1a(2) =2a(3) =7a(4) =17a(5) =47a(6) =121a(7) =320a(8) =835a(9) =2190a(10) =5730a(11) =15006a(12) =39282a(13) =102847a(14) =269252a(15) =704917a(16) =1845491a(17) =4831565a(18) =12649195a(19) =33116030a(20) =86698885a(21) =226980636a(22) =594243012a(23) =1555748412a(24) =4073002212a(25) =10663258237a(26) =27916772486a(27) =73087059235