OFFSET
1,1
FORMULA
Lim_{n->infinity} a(n+1)/a(n) = 1 (conjectured).
EXAMPLE
MATHEMATICA
PellSolve[(m_Integer)?Positive] :=
Module[{cf, n, s}, cof = ContinuedFraction[Sqrt[m]];
n = Length[Last[cof]]; If[OddQ[n], n = 2*n];
s = FromContinuedFraction[
ContinuedFraction[Sqrt[m], n]]; {Numerator[s], Denominator[s]}];
f[n_] := If[! IntegerQ[Sqrt[n]], PellSolve[n][[2]]];
Select[Range[250], Mod[#, f[#]] == 0 &]
CROSSREFS
KEYWORD
nonn
AUTHOR
Salvador Cerdá, Nov 16 2016
EXTENSIONS
More terms from Michel Marcus, Dec 04 2016
STATUS
approved