a(n) = ceiling(n*phi^3), where phi is the golden ratio, A001622.

Terms

a(0) =0a(1) =5a(2) =9a(3) =13a(4) =17a(5) =22a(6) =26a(7) =30a(8) =34a(9) =39a(10) =43a(11) =47a(12) =51a(13) =56a(14) =60a(15) =64a(16) =68a(17) =73a(18) =77a(19) =81a(20) =85a(21) =89a(22) =94a(23) =98a(24) =102a(25) =106a(26) =111a(27) =115a(28) =119a(29) =123