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

Terms

a(0) =1a(1) =4a(2) =646a(3) =1096a(4) =16174a(5) =22891a(6) =64672a(7) =353110a(8) =468970a(9) =515698a(10) =733570a(11) =1317343a(12) =1633213a(13) =1735288a(14) =2026945a(15) =2093506a(16) =2709542a(17) =4413772a(18) =5005825a(19) =5346241a(20) =5388154a(21) =6134527a(22) =12811666a(23) =15453229a(24) =19063174a(25) =20565214a(26) =22172791a(27) =35476021