Floor((quadronacci ratio)^n).

Terms

a(0) =1a(1) =3a(2) =7a(3) =13a(4) =26a(5) =51a(6) =98a(7) =190a(8) =367a(9) =708a(10) =1364a(11) =2630a(12) =5071a(13) =9775a(14) =18841a(15) =36318a(16) =70007a(17) =134942a(18) =260110a(19) =501380a(20) =966441a(21) =1862874a(22) =3590806a(23) =6921503a(24) =13341626a(25) =25716810a(26) =49570746a(27) =95550687a(28) =184179871a(29) =355018115