Numbers k such that phi(k) divides sigma(k+1) + sigma(k).

Terms

a(0) =1a(1) =2a(2) =6a(3) =8a(4) =11a(5) =14a(6) =22a(7) =30a(8) =70a(9) =86a(10) =102a(11) =116a(12) =130a(13) =140a(14) =154a(15) =186a(16) =238a(17) =286a(18) =390a(19) =406a(20) =422a(21) =454a(22) =459a(23) =646a(24) =830a(25) =869a(26) =1015a(27) =1070a(28) =1120a(29) =1518