0,2

a(n)=(1/(10*Sqrt[2]) ((1 + Sqrt[2])^(3^n) - (1 - Sqrt[2])^(3^n)) a[n+1]= 200 a[n]^3 - 3 a[n] a[0]=1

1) Table[Simplify[Expand[(1/(10 Sqrt[2]) ((1 + Sqrt[2])^(3^n) + (1 - Sqrt[2])^(3^n))]], {n, 0, 5}]

2) a = {}; k = 1; Do[AppendTo[a, k]; k = 200 k^3 - 3 k, {n, 1, 6}]; a (*Artur Jasinski*)

A006266, A145451

Sequence in context: A031602 A097733 A114050 this_sequence A025375 A031512 A025366

Adjacent sequences: A145449 A145450 A145451 this_sequence A145453 A145454 A145455

nonn

Artur Jasinski (grafix(AT)csl.pl), Oct 10 2008