%I A075871
%S A075871 0,180,233640,303264540,393637139280,510940703520900,
%T A075871 663200639532988920,860833919173116097260,1117361763886065161254560,
%U A075871 1450334708690193406192321620,1882533334518107155172472208200
%N A075871 Numbers n such that 13*n^2 + 1 is a square.
%C A075871 Lim_{n-> Inf.} a(n)/a(n-1) = 649 + 180*Sqrt(13).
%H A075871 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/
               RecursiveSequences.html">Recursive Sequences</a>
%F A075871 a(n)=1298*a(n-1)-a(n-2), n>1. - Michael Somos, Oct 30 2002
%F A075871 a(n) = [(649+180*Sqrt(13))^n - (649-180*Sqrt(13))^n] / (2*Sqrt(13))
%F A075871 a(n) = 1297*(a(n-1)+a(n-2))-a(n-3). a(n) = 1299*(a(n-1)-a(n-2))+a(n-3). 
               - Mohamed Bouhamida (bhmd95(AT)yahoo.fr), Sep 20 2006
%F A075871 G.f.: 180x^2/(1-1298x+x^2). [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), 
               Nov 18 2008]
%Y A075871 Sequence in context: A091033 A146530 A057867 this_sequence A074811 A036200 
               A157747
%Y A075871 Adjacent sequences: A075868 A075869 A075870 this_sequence A075872 A075873 
               A075874
%K A075871 nonn
%O A075871 1,2
%A A075871 Gregory V. Richardson (omomom(AT)hotmail.com), Oct 16 2002