Numbers k such that sigma(k) = 2*phi(k+1).

Terms

a(0) =3a(1) =6a(2) =7a(3) =28a(4) =31a(5) =94a(6) =127a(7) =322a(8) =406a(9) =1990a(10) =2488a(11) =3154a(12) =4402a(13) =7258a(14) =8191a(15) =12466a(16) =13114a(17) =14146a(18) =25870a(19) =29116a(20) =31456a(21) =36442a(22) =43030a(23) =46606a(24) =61132a(25) =64354a(26) =65248a(27) =67252a(28) =76456a(29) =86332