Sum of divisors of 2^n+1.

Terms

a(0) =4a(1) =6a(2) =13a(3) =18a(4) =48a(5) =84a(6) =176a(7) =258a(8) =800a(9) =1302a(10) =2736a(11) =4356a(12) =10928a(13) =20520a(14) =51792a(15) =65538a(16) =174768a(17) =351120a(18) =699056a(19) =1110276a(20) =3100240a(21) =5048232a(22) =11184816a(23) =17041416a(24) =49012992a(25) =82623888a(26) =211053040a(27) =284225796a(28) =727960800a(29) =1494039792