Self-convolution of the Dedekind psi function (A001615).

Terms

a(0) =0a(1) =1a(2) =6a(3) =17a(4) =36a(5) =64a(6) =108a(7) =172a(8) =240a(9) =340a(10) =444a(11) =612a(12) =744a(13) =980a(14) =1164a(15) =1504a(16) =1704a(17) =2172a(18) =2388a(19) =2964a(20) =3288a(21) =3968a(22) =4272a(23) =5272a(24) =5520a(25) =6624a(26) =7104a(27) =8276a(28) =8640a(29) =10404