a(n) = Sum_{k=1..n} phi(gcd(k, n))^3.

Terms

a(0) =1a(1) =2a(2) =10a(3) =11a(4) =68a(5) =20a(6) =222a(7) =78a(8) =238a(9) =136a(10) =1010a(11) =110a(12) =1740a(13) =444a(14) =680a(15) =604a(16) =4112a(17) =476a(18) =5850a(19) =748a(20) =2220a(21) =2020a(22) =10670a(23) =780a(24) =8276a(25) =3480a(26) =6330a(27) =2442a(28) =21980a(29) =1360