a(n) = Sum_{k=1..n} gcd(k, n)^4.

Terms

a(0) =1a(1) =17a(2) =83a(3) =274a(4) =629a(5) =1411a(6) =2407a(7) =4388a(8) =6729a(9) =10693a(10) =14651a(11) =22742a(12) =28573a(13) =40919a(14) =52207a(15) =70216a(16) =83537a(17) =114393a(18) =130339a(19) =172346a(20) =199781a(21) =249067a(22) =279863a(23) =364204a(24) =393145a(25) =485741a(26) =545067a(27) =659518a(28) =707309a(29) =887519