a(n) = Sum_{k=1..n} gcd(k, n)^5.

Terms

a(0) =1a(1) =33a(2) =245a(3) =1058a(4) =3129a(5) =8085a(6) =16813a(7) =33860a(8) =59541a(9) =103257a(10) =161061a(11) =259210a(12) =371305a(13) =554829a(14) =766605a(15) =1083528a(16) =1419873a(17) =1964853a(18) =2476117a(19) =3310482a(20) =4119185a(21) =5315013a(22) =6436365a(23) =8295700a(24) =9778145a(25) =12253065a(26) =14468481a(27) =17788154a(28) =20511177a(29) =25297965