a(n) = Sum_{k >= 1} floor(3*tau^(n-k)).

Terms

a(0) =5a(1) =9a(2) =16a(3) =28a(4) =48a(5) =81a(6) =134a(7) =221a(8) =361a(9) =589a(10) =957a(11) =1554a(12) =2519a(13) =4082a(14) =6610a(15) =10702a(16) =17322a(17) =28035a(18) =45368a(19) =73415a(20) =118795a(21) =192223a(22) =311031a(23) =503268a(24) =814313a(25) =1317596a(26) =2131924a(27) =3449536a(28) =5581476a(29) =9031029