a(n) = 1^n + 3^n + 5^n + 7^n.

Terms

a(0) =4a(1) =16a(2) =84a(3) =496a(4) =3108a(5) =20176a(6) =134004a(7) =903856a(8) =6161988a(9) =42326416a(10) =292299924a(11) =2026332016a(12) =14085959268a(13) =98111307856a(14) =684331371444