a(n) = Sum_{i=1..n} Sum_{j=1..n} Sum_{k=1..n} phi(i*j*k).

Terms

a(0) =1a(1) =14a(2) =98a(3) =412a(4) =1436a(5) =3212a(6) =8312a(7) =17460a(8) =34182a(9) =57406a(10) =107306a(11) =161942a(12) =277550a(13) =406490a(14) =581210a(15) =850162a(16) =1292018a(17) =1701752a(18) =2481476a(19) =3216100a(20) =4184464a(21) =5406704a(22) =7414512a(23) =9119640a(24) =11849180a(25) =14736284a(26) =18541664a(27) =22500200a(28) =28950168a(29) =33410736