Numbers k such that phi(k)*sigma(k) is a fourth power.

Terms

a(0) =1a(1) =170a(2) =595a(3) =714a(4) =121056a(5) =480441a(6) =529620a(7) =706063a(8) =706237a(9) =729752a(10) =755972a(11) =815654a(12) =2162808a(13) =2449062a(14) =2827789a(15) =2927848a(16) =2957416a(17) =2994681a(18) =2995419a(19) =3010227a(20) =3019028a(21) =3019772a(22) =3080140a(23) =3093860a(24) =3103464a(25) =3206364a(26) =3213804