a(n) = Sum_{d divides n} (-1)^(d + n/d) * d^4.

Terms

a(0) =1a(1) =-17a(2) =82a(3) =-241a(4) =626a(5) =-1394a(6) =2402a(7) =-3825a(8) =6643a(9) =-10642a(10) =14642a(11) =-19762a(12) =28562a(13) =-40834a(14) =51332a(15) =-61169a(16) =83522a(17) =-112931a(18) =130322a(19) =-150866a(20) =196964a(21) =-248914a(22) =279842a(23) =-313650a(24) =391251a(25) =-485554a(26) =538084a(27) =-578882a(28) =707282a(29) =-872644