a(n) = 1^n + 2^n + 3^n + 4^n.

Terms

a(0) =4a(1) =10a(2) =30a(3) =100a(4) =354a(5) =1300a(6) =4890a(7) =18700a(8) =72354a(9) =282340a(10) =1108650a(11) =4373500a(12) =17312754a(13) =68711380a(14) =273234810a(15) =1088123500a(16) =4338079554a(17) =17309140420a(18) =69107159370a(19) =276040692700