%I A099194
%S A099194 2,5,10,13,29,61,109,397,1021,2389,6829,25309,82021,271021,952429
%N A099194 Least solution to the Pellian equation x^2 - k*y^2 = 1 (A002349) such 
               that 2^2^n < y <= 2^2^(n+1).
%t A099194 $MaxExtraPrecision = 512; PellSolve[(m_Integer)?Positive] := Module[{cf, 
               n, s}, cf = ContinuedFraction[ Sqrt[m]]; n = Length[ Last[cf]]; 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]], 0]; t = Table[0, {20}]; Do[a = Floor[ 
               Log[2, Log[2, f[n]]]]; If[a < 20 && t[[a - 1]] == 0, t[[a - 1]] = 
               n; Print[{a, n}]], {n, 10^7}]
%Y A099194 Cf. A002349, A002350, A069039, A099193.
%Y A099194 Sequence in context: A064392 A018296 A033316 this_sequence A140411 A053353 
               A099792
%Y A099194 Adjacent sequences: A099191 A099192 A099193 this_sequence A099195 A099196 
               A099197
%K A099194 hard,nonn
%O A099194 -1,1
%A A099194 Robert G. Wilson v (rgwv(AT)rgwv.com), Oct 02 2004