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

Terms

a(0) =2a(1) =21a(2) =51a(3) =369a(4) =3051a(5) =3783a(6) =5757a(7) =6477a(8) =6897a(9) =7929a(10) =15639a(11) =15925a(12) =20967a(13) =33003a(14) =50739a(15) =58797a(16) =73917a(17) =75627a(18) =118405a(19) =121975a(20) =131979a(21) =170973a(22) =219447a(23) =291369a(24) =310137a(25) =311675a(26) =347337a(27) =365679a(28) =396807a(29) =404559