a(n) = Sum_{1 <= x_1, x_2, x_3 <= n} ( gcd(x_1, n)/gcd(x_1, x_2, x_3, n) )^2.

Terms

a(0) =1a(1) =17a(2) =91a(3) =289a(4) =701a(5) =1547a(6) =2647a(7) =4769a(8) =7705a(9) =11917a(10) =15731a(11) =26299a(12) =30421a(13) =44999a(14) =63791a(15) =77473a(16) =87857a(17) =130985a(18) =136459a(19) =202589a(20) =240877a(21) =267427a(22) =290951a(23) =433979a(24) =448201a(25) =517157a(26) =633187a(27) =764983a(28) =729989a(29) =1084447