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 A153317 #27 Aug 21 2025 06:45:32 %S A153317 1,10,21,220,461,4830,10121,106040,222201,2328050,4878301,51111060, %T A153317 107100421,1122115270,2351330961,24635424880,51622180721,540857232090, %U A153317 1133336644901,11874223681100,24881784007101,260692063752110,546265911511321,5723351178865320,11992968269241961 %N A153317 Denominators of continued fraction convergents to sqrt(6/5). %H A153317 Paolo Xausa, <a href="/A153317/b153317.txt">Table of n, a(n) for n = 0..1000</a> %H A153317 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,22,0,-1). %F A153317 For n>0, a(2*n) = 2*a(2*n-1) + a(2*n-2) and a(2*n+1) = 10*a(2*n) + a(2*n-1). %F A153317 G.f.: (1+10*x-x^2)/(1-22*x^2+x^4). - _Colin Barker_, Jan 01 2012 %e A153317 The initial convergents are 1, 11/10, 23/21, 241/220, 505/461, 5291/4830, 11087/10121, 116161/106040, 243409/222201, 2550251/2328050, 55989361/4878301, ... %t A153317 Denominator[Convergents[Sqrt[6/5], 25]] (* _Paolo Xausa_, Jan 16 2025 *) %Y A153317 Cf. A000129, A001333, A142238, A142239, A153315, A153316, A153318. %K A153317 nonn,changed %O A153317 0,2 %A A153317 _Charlie Marion_, Jan 07 2009