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 A098292 #31 Sep 08 2022 08:45:15 %S A098292 1,730,533629,390082069,285149458810,208443864308041, %T A098292 152372179659719161,111383854887390398650,81421445550502721693989, %U A098292 59518965313562602167907309,43508282222768711682018548890 %N A098292 First differences of Chebyshev polynomials S(n,731)=A098263(n) with Diophantine property. %C A098292 (27*b(n))^2 - 733*a(n)^2 = -4 with b(n)=A098291(n) give all positive solutions of this Pell equation. %H A098292 G. C. Greubel, <a href="/A098292/b098292.txt">Table of n, a(n) for n = 0..340</a> %H A098292 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a> %H A098292 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 A098292 <a href="/index/Ch#Cheby">Index entries for sequences related to Chebyshev polynomials.</a> %H A098292 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (731,-1). %F A098292 a(n) = ((-1)^n)*S(2*n, 27*i) with the imaginary unit i and the S(n, x) = U(n, x/2) Chebyshev polynomials. %F A098292 G.f.: (1-x)/(1-731*x+x^2). %F A098292 a(n) = S(n, 731) - S(n-1, 731) = T(2*n+1, sqrt(733)/2)/(sqrt(733)/2), with S(n, x) = U(n, x/2) Chebyshev's polynomials of the second kind, A049310. S(-1, x)= 0 = U(-1, x) and T(n, x) Chebyshev's polynomials of the first kind, A053120. %F A098292 a(n) = 731*a(n-1) - a(n-2), n > 1; a(0)=1, a(1)=730. - _Philippe Deléham_, Nov 18 2008 %e A098292 All positive solutions of Pell equation x^2 - 733*y^2 = -4 are (27=27*1,1), (19764=27*732,730), (14447457=27*535091,533629), (10561071303=27*391150789,390082069), ... %t A098292 LinearRecurrence[{731,-1},{1,730},20] (* _Harvey P. Dale_, Nov 15 2013 *) %o A098292 (PARI) my(x='x+O('x^20)); Vec((1-x)/(1-731*x+x^2)) \\ _G. C. Greubel_, Aug 01 2019 %o A098292 (Magma) I:=[1,730]; [n le 2 select I[n] else 731*Self(n-1) - Self(n-2): n in [1..20]]; // _G. C. Greubel_, Aug 01 2019 %o A098292 (Sage) ((1-x)/(1-731*x+x^2)).series(x, 20).coefficients(x, sparse=False) # _G. C. Greubel_, Aug 01 2019 %o A098292 (GAP) a:=[1,730];; for n in [3..20] do a[n]:=731*a[n-1]-a[n-2]; od; a; # _G. C. Greubel_, Aug 01 2019 %Y A098292 Cf. A098291. %K A098292 nonn,easy %O A098292 0,2 %A A098292 _Wolfdieter Lang_, Sep 10 2004