sigma_4(n): sum of 4th powers of divisors of n.

Terms

a(0) =1a(1) =17a(2) =82a(3) =273a(4) =626a(5) =1394a(6) =2402a(7) =4369a(8) =6643a(9) =10642a(10) =14642a(11) =22386a(12) =28562a(13) =40834a(14) =51332a(15) =69905a(16) =83522a(17) =112931a(18) =130322a(19) =170898a(20) =196964a(21) =248914a(22) =279842a(23) =358258a(24) =391251a(25) =485554a(26) =538084a(27) =655746a(28) =707282a(29) =872644