Numbers k such that sigma(k) = phi(prime(k)-1).

Terms

a(0) =1a(1) =7a(2) =19a(3) =47a(4) =115a(5) =177a(6) =280a(7) =297a(8) =340a(9) =406a(10) =470a(11) =930a(12) =1240a(13) =1608a(14) =1836a(15) =2232a(16) =2380a(17) =2484a(18) =4326a(19) =8360a(20) =33864a(21) =166152a(22) =216216a(23) =220248a(24) =299250a(25) =394500