Powers of cube root of 18 rounded up.

Terms

a(0) =1a(1) =3a(2) =7a(3) =18a(4) =48a(5) =124a(6) =324a(7) =850a(8) =2226a(9) =5832a(10) =15285a(11) =40056a(12) =104976a(13) =275115a(14) =721006a(15) =1889568a(16) =4952070a(17) =12978093a(18) =34012224a(19) =89137244a(20) =233605664a(21) =612220032a(22) =1604470381a(23) =4204901942a(24) =11019960576a(25) =28880466845a(26) =75688234943a(27) =198359290368a(28) =519848403194