A069255 a(n) = (2^((2*n-1)^2)+1)/(2^(2*n-1)+1).

1, 57, 1016801, 4363953127297, 4713161090115513351681, 1297440698667560637290197228189697, 91332703321545501540374299322682400349546864641, 1645454342039771722949556903599110786025642797921240958290067457, 7588492464653843921408409789152927606760448769729047438304822150910706202078740481

Offset: 1

Author

Benoit Cloitre, Apr 14 2002

Keywords

• easy
• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..29

Programs

Mathematica

a[n_] := (2^((2*n-1)^2)+1)/(2^(2*n-1)+1); Array[a, 9] (* Amiram Eldar, May 01 2025 *)