Numbers m that divide sigma(sigma(m) - m) where sigma is the sum of divisors function (A000203).

Terms

a(0) =4a(1) =6a(2) =8a(3) =28a(4) =32a(5) =36a(6) =78a(7) =84a(8) =128a(9) =168a(10) =252a(11) =496a(12) =504a(13) =532a(14) =756a(15) =1488a(16) =2808a(17) =3720a(18) =4464a(19) =5928a(20) =8128a(21) =8192a(22) =13392a(23) =24384a(24) =61236a(25) =73152a(26) =78120a(27) =131072a(28) =183708a(29) =217728