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

Terms

a(0) =1a(1) =9a(2) =225a(3) =242a(4) =516a(5) =729a(6) =3872a(7) =13932a(8) =14406a(9) =17672a(10) =18225a(11) =20124a(12) =21780a(13) =29262a(14) =29616a(15) =45996a(16) =65025a(17) =76832a(18) =92778a(19) =95916a(20) =106092a(21) =106308a(22) =114630a(23) =114930a(24) =121872a(25) =125652a(26) =140130a(27) =140625a(28) =145794a(29) =149124