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%I #16 Nov 21 2020 05:08:05
%S 0,2,4,6,180,1820,3588,9100,226153980,15140424455100,
%T 183567298683461940,9562401173878027020,42094239791738433660,
%U 1238789998647218582160,189073995951839020880499780706260
%N Incrementally largest values of minimal y satisfying Pell equation x^2-Dy^2=1.
%C Records in A033317 (or A002349).
%H Ray Chandler, <a href="/A033319/b033319.txt">Table of n, a(n) for n = 1..63</a>
%H N. J. A. Sloane et al., <a href="https://oeis.org/wiki/Binary_Quadratic_Forms_and_OEIS">Binary Quadratic Forms and OEIS</a> (Index to related sequences, programs, references)
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/PellEquation.html">Pell Equation</a>.
%t PellSolve[(m_Integer)?Positive] := Module[{cf, n, s}, cf = ContinuedFraction[Sqrt[m]]; n = Length[Last[cf]]; If[n == 0, Return[{}]]; If[OddQ[n], n = 2 n]; s = FromContinuedFraction[ ContinuedFraction[ Sqrt[m], n]]; {Numerator[s], Denominator[s]}];
%t yy = DeleteCases[PellSolve /@ Range[10^5], {}][[All, 2]];
%t Reap[Module[{y, record = 0}, Sow[0]; For[i = 1, i <= Length@yy, i++, y = yy[[i]]; If[y > record, record = y; Sow[y]]]]][[2, 1]] (* _Jean-François Alcover_, Nov 21 2020, after _N. J. A. Sloane_ in A002350 *)
%Y Cf. A000037, A033317, A033318, A002349, A002350, A033316.
%K nonn
%O 1,2
%A _Eric W. Weisstein_
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