a(0) = 397; a(n+1) = a(n)^2 if a(n) is prime, floor(a(n)/2) otherwise.

Terms

a(0) =397a(1) =157609a(2) =78804a(3) =39402a(4) =19701a(5) =9850a(6) =4925a(7) =2462a(8) =1231a(9) =1515361a(10) =757680a(11) =378840a(12) =189420a(13) =94710a(14) =47355a(15) =23677a(16) =560600329a(17) =280300164a(18) =140150082a(19) =70075041a(20) =35037520a(21) =17518760a(22) =8759380a(23) =4379690a(24) =2189845a(25) =1094922a(26) =547461a(27) =273730a(28) =136865a(29) =68432