Integers k such that sigma(k)/k - 1 is a rational square.

Terms

a(0) =1a(1) =6a(2) =9a(3) =28a(4) =216a(5) =360a(6) =496a(7) =2016a(8) =2401a(9) =8128a(10) =16758a(11) =182520a(12) =884736a(13) =1022112a(14) =1352328a(15) =1571328a(16) =1935360a(17) =2678400a(18) =33550336a(19) =54758400a(20) =101382400a(21) =119533176a(22) =136808280a(23) =163298502a(24) =198288000a(25) =618591192a(26) =691022088a(27) =782481673a(28) =796663296a(29) =1137067008