Sqrt[a(n)a(n+1)+1] of A051047.

Terms

a(0) =2a(1) =5a(2) =31a(3) =449a(4) =6271a(5) =87361a(6) =1216799a(7) =16947841a(8) =236052991a(9) =3287794049a(10) =45793063711a(11) =637815097921