Numbers k for which sigma(k)/k - 4/7 is an integer.

Terms

a(0) =280a(1) =18620a(2) =411264a(3) =804384a(4) =871416a(5) =1222144a(6) =1284192a(7) =164989440a(8) =270138960a(9) =318729600a(10) =326781000a(11) =396168192a(12) =481572000a(13) =623397600a(14) =675347400a(15) =995248800a(16) =3444711424a(17) =4426793280a(18) =307030348800a(19) =465036042240a(20) =880719036120