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%I #8 Apr 30 2012 13:29:07
%S 3202,3554,6178,6274,6626,7522,8354,9442,9634,12706,12962,14978,15586,
%T 16418,16546,18754,19298,22114,24098,24482
%N Beach-Williams Pell numbers of type 2p (p prime).
%C Consider the problem of finding all integers n such that the Pell equation x^2 - n*y^2 = -1 is solvable in integers x,y with y != 0. Beach and Williams found that there are 102662 such values of n in the range 1 <= n <= 10^6.
%C Of these, 3531 "exceptional" values of n were not predicted by a certain list of criteria given in their paper. These 3531 exceptional values fall into 10 classes given in sequences A212074-A212083.
%D Beach, B. D. and Williams, H. C., A numerical investigation of the Diophantine equation x^2-dy^2=-1. Proceedings of the Third Southeastern Conference on Combinatorics, Graph Theory and Computing (Florida Atlantic Univ., Boca Raton, Fla., 1972), pp. 37-68. Florida Atlantic Univ., Boca Raton, Fla., 1972.
%Y Cf. A212074-A212083.
%K nonn
%O 1,1
%A _N. J. A. Sloane_, Apr 30 2012