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

Terms

a(0) =2a(1) =3a(2) =5a(3) =115a(4) =143a(5) =287a(6) =371a(7) =413a(8) =623a(9) =791a(10) =4067a(11) =10031a(12) =24149a(13) =32335a(14) =39689a(15) =88403a(16) =93443a(17) =107365a(18) =148735a(19) =168833a(20) =212993a(21) =427763a(22) =555947a(23) =650095a(24) =925253a(25) =1017821a(26) =1117457a(27) =1139467a(28) =1229327a(29) =1270801