a(n) = 1^n + 5^n + 6^n.

Terms

a(0) =3a(1) =12a(2) =62a(3) =342a(4) =1922a(5) =10902a(6) =62282a(7) =358062a(8) =2070242a(9) =12030822a(10) =70231802a(11) =411625182a(12) =2420922962a(13) =14281397142a(14) =84467679722a(15) =500702562702