a(n) = Sum_{1 <= x_1, x_2 <= n} gcd(x_1, x_2, n)^5.

Terms

a(0) =1a(1) =35a(2) =251a(3) =1132a(4) =3149a(5) =8785a(6) =16855a(7) =36272a(8) =61065a(9) =110215a(10) =161171a(11) =284132a(12) =371461a(13) =589925a(14) =790399a(15) =1160896a(16) =1420145a(17) =2137275a(18) =2476459a(19) =3564668a(20) =4230605a(21) =5640985a(22) =6436871a(23) =9104272a(24) =9841225a(25) =13001135a(26) =14839443a(27) =19079860a(28) =20511989a(29) =27663965