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 A042281 #13 Jul 09 2025 02:31:15 %S A042281 1,1,5,26,31,57,373,430,2093,2523,17231,19754,36985,204679,855701, %T A042281 1060380,53874701,54935081,273615025,1423010206,1696625231,3119635437, %U A042281 20414437853,23534073290,114550731013,138084804303,943059556831,1081144361134,2024203917965 %N A042281 Denominators of continued fraction convergents to sqrt(666). %H A042281 Vincenzo Librandi, <a href="/A042281/b042281.txt">Table of n, a(n) for n = 0..200</a> %H A042281 <a href="/index/Rec#order_32">Index entries for linear recurrences with constant coefficients</a>, signature (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 54730402, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1). %t A042281 Denominator[Convergents[Sqrt[666], 30]] (* _Vincenzo Librandi_, Jan 19 2014 *) %Y A042281 Cf. A042280. %K A042281 nonn,frac,easy %O A042281 0,3 %A A042281 _N. J. A. Sloane_ %E A042281 More terms from _Vincenzo Librandi_, Jan 19 2014