Numbers k such that k = phi(sigma(phi(sigma(phi(sigma(k)))))).

Terms

a(0) =1a(1) =2a(2) =8a(3) =12a(4) =16a(5) =24a(6) =30a(7) =128a(8) =240a(9) =720a(10) =1200a(11) =1536a(12) =1860a(13) =6912a(14) =15552a(15) =15840a(16) =18144a(17) =32768a(18) =67392a(19) =83160a(20) =92160a(21) =142560a(22) =272160a(23) =290304a(24) =290400a(25) =712800a(26) =1140480a(27) =1190400a(28) =3345408a(29) =3571200