a(n) = sigma_4(n^4)/sigma_2(n^4).

Terms

a(0) =1a(1) =205a(2) =5905a(3) =52429a(4) =375601a(5) =1210525a(6) =5649505a(7) =13421773a(8) =38742049a(9) =76998205a(10) =212601841a(11) =309593245a(12) =810932305a(13) =1158148525a(14) =2217923905a(15) =3435973837a(16) =6951703105a(17) =7942120045a(18) =16936647121a(19) =19692384829a(20) =33360327025a(21) =43583377405a(22) =78163228705a(23) =79255569565a(24) =146719125601