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

Terms

a(0) =1a(1) =5a(2) =19a(3) =47a(4) =115a(5) =183a(6) =369a(7) =585a(8) =927a(9) =1271a(10) =2021a(11) =2557a(12) =3817a(13) =4813a(14) =6101a(15) =7749a(16) =10581a(17) =12381a(18) =16395a(19) =19147a(20) =22855a(21) =26795a(22) =33901a(23) =38141a(24) =46081a(25) =52729a(26) =61711a(27) =69487a(28) =83851a(29) =90731