Number of cubic residues mod 4^n.

Terms

a(0) =1a(1) =3a(2) =10a(3) =37a(4) =147a(5) =586a(6) =2341a(7) =9363a(8) =37450a(9) =149797a(10) =599187a(11) =2396746a(12) =9586981a(13) =38347923a(14) =153391690a(15) =613566757a(16) =2454267027a(17) =9817068106a(18) =39268272421a(19) =157073089683a(20) =628292358730