A145506 a(n+1) = a(n)^2+2*a(n)-2 and a(1)=6.

6, 46, 2206, 4870846, 23725150497406, 562882766124611619513723646, 316837008400094222150776738483768236006420971486980606

Offset: 1

Author

Artur Jasinski, Oct 11 2008

Keywords

• nonn

Comments

General formula for a(n+1) = a(n)^2+2*a(n)-2 and a(1) = k+1 is a(n) = floor(((k + sqrt(k^2 + 4))/2)^(2^((n+1) - 1))).

Essentially the same as A145502. - R. J. Mathar, Mar 18 2009

Crossrefs

Cf. A145502-A145511.

Programs

Mathematica

aa = {}; k = 6; Do[AppendTo[aa, k]; k = k^2 + 2 k - 2, {n, 1, 10}]; aa
or
k = 5; Table[Floor[((k + Sqrt[k^2 + 4])/2)^(2^(n - 1))], {n, 2, 7}] (* Artur Jasinski *)