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%I #27 Oct 22 2019 21:19:35
%S 1,2,4,5,8,9,10,13,16,17,18,20,25,26,29,32,36,37,40,41,45,49,50,52,53,
%T 58,61,64,65,68,72,73,74,80,81,82,85,89,90,97,98,100,101,104,106,109,
%U 113,116,117,121,122,125,128,130,137,144,145,148,149,153,157
%N Values of n such that the equation x^2 - n*y^2 = n has integer solutions.
%C All the squares are in this sequence.
%C Differs from A001481 \ {0} and A248151 from a(17) = 36 on. The number 0 is in the sequence according to its definition. - _M. F. Hasler_, Oct 22 2019
%e 5 is in the sequence because x^2-5*y^2=5 has integer solutions, including (x,y) = (5,2) and (85,38).
%t Select[Range[1,200],Solve[x^2==#*(1+y^2),{x,y},Integers]!={}&] (* _Vaclav Kotesovec_, Jul 15 2014 *)
%K nonn
%O 1,2
%A _Colin Barker_, Jul 14 2014