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 A097738 #37 Sep 08 2022 08:45:14 %S A097738 1,327,106601,34751599,11328914673,3693191431799,1203969077851801, %T A097738 392490226188255327,127950609768293384801,41711506294237455189799, %U A097738 13597823101311642098489673,4432848619521301086652443599,1445095052140842842606598123601 %N A097738 Pell equation solutions (9*a(n))^2 - 82*b(n)^2 = -1 with b(n):=A097739(n), n >= 0. %H A097738 Indranil Ghosh, <a href="/A097738/b097738.txt">Table of n, a(n) for n = 0..397</a> %H A097738 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a> %H A097738 Giovanni Lucca, <a href="http://forumgeom.fau.edu/FG2019volume19/FG201902index.html">Integer Sequences and Circle Chains Inside a Hyperbola</a>, Forum Geometricorum (2019) Vol. 19, 11-16. %H A097738 <a href="/index/Ch#Cheby">Index entries for sequences related to Chebyshev polynomials.</a> %H A097738 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (326,-1). %F A097738 G.f.: (1 + x)/(1 - 2*163*x + x^2). %F A097738 a(n) = S(n, 2*163) + S(n-1, 2*163) = S(2*n, 2*sqrt(82)), with Chebyshev polynomials of the 2nd kind. See A049310 for the triangle of S(n, x) = U(n, x/2) coefficients. S(-1, x) := 0 =: U(-1, x). %F A097738 a(n) = ((-1)^n)*T(2*n+1, 9*i)/(9*i) with the imaginary unit i and Chebyshev polynomials of the first kind. See the T-triangle A053120. %F A097738 a(n) = 326*a(n-1) - a(n-2), n>1; a(0)=1, a(1)=327. - _Philippe Deléham_, Nov 18 2008 %F A097738 a(n) = (1/9)*sinh((2*n + 1)*arcsinh(9)). - _Bruno Berselli_, Apr 03 2018 %e A097738 (x,y) = (9*1=9;1), (2943=9*327;325), (959409=9*106601;105949), ... give the positive integer solutions to x^2 - 82*y^2 =-1. %t A097738 LinearRecurrence[{326, -1}, {1, 327}, 12] (* _Ray Chandler_, Aug 12 2015 *) %o A097738 (PARI) x='x+O('x^99); Vec((1+x)/(1-2*163*x+x^2)) \\ _Altug Alkan_, Apr 05 2018 %o A097738 (Magma) a:=[1,327]; [n le 2 select a[n] else 326*Self(n-1) - Self(n-2): n in [1..13]]; // _Marius A. Burtea_, Jan 23 2020 %o A097738 (Magma) R<x>:=PowerSeriesRing(Integers(), 13); Coefficients(R!( (1 + x)/(1 - 2*163*x + x^2))); // _Marius A. Burtea_, Jan 23 2020 %Y A097738 Cf. A097737 for S(n, 2*163). %Y A097738 Cf. similar sequences of the type (1/k)*sinh((2*n+1)*arcsinh(k)) listed in A097775. %K A097738 nonn,easy %O A097738 0,2 %A A097738 _Wolfdieter Lang_, Aug 31 2004