This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A307169 #11 Apr 01 2019 03:00:34 %S A307169 4,65,1036,16511,263140,4193729,66836524,1065190655,16976213956, %T A307169 270554232641,4311891508300,68719709900159,1095203466894244, %U A307169 17454535760407745,278177368699629676,4433383363433667071,70655956446239043460,1126061919776391028289,17946334759976017409164 %N A307169 First class of all proper positive solutions y1(n) = a(n) of the Pell equation x^2 - 7*y^2 = 9. %C A307169 The corresponding x1 solutions are given in A307168. %C A307169 For details see A307168. %H A307169 <a href="/index/Ch#Cheby">Index entries for sequences related to Chebyshev polynomials.</a> %H A307169 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (16,-1). %F A307169 G.f.: x*(4 + x)/(1 - 16*x + x^2). %F A307169 a(n) = -S(n, 16) + 20*S(n-1, 16) for n >= 1, with S(n,16) = A077412(n). %F A307169 a(n) = sqrt((A307168(n)^2 - 9)/7) for n >= 1. %Y A307169 Cf. A077412, A307168. %K A307169 nonn,easy %O A307169 1,1 %A A307169 _Wolfdieter Lang_, Mar 27 2019