Numbers n such that sigma(n+1) - sigma(n-1) = n+1.

Terms

a(0) =2a(1) =3a(2) =23a(3) =14927a(4) =31049a(5) =69107a(6) =246263a(7) =5860169a(8) =307164671a(9) =881198663a(10) =1489455647a(11) =2386555631a(12) =8225563703a(13) =14311679063a(14) =111494234183a(15) =154357775303a(16) =299004519623a(17) =870455062823a(18) =970388922263a(19) =991817878343