Numbers k such that k + sigma(k) + phi(k) is a square.

Terms

a(0) =3a(1) =81a(2) =400a(3) =972a(4) =1209a(5) =1276a(6) =1480a(7) =1833a(8) =2700a(9) =3408a(10) =4080a(11) =4345a(12) =6321a(13) =6498a(14) =6885a(15) =8673a(16) =8697a(17) =10257a(18) =12325a(19) =13192a(20) =13240a(21) =13409a(22) =14496a(23) =14560a(24) =16932a(25) =17232a(26) =18168a(27) =18904a(28) =19140a(29) =19344