a(n) = A076969(n)^(1/3).

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =5a(5) =7a(6) =9a(7) =11a(8) =14a(9) =18a(10) =23a(11) =29a(12) =37a(13) =47a(14) =59a(15) =75a(16) =94a(17) =119a(18) =150a(19) =189a(20) =238a(21) =300a(22) =378a(23) =477a(24) =601a(25) =757a(26) =954a(27) =1202a(28) =1515a(29) =1909