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 A215485 #21 Nov 24 2024 10:06:14 %S A215485 0,1,2,3,7,9,13,19,23,27,35,41,43,45,53,55,71,77,101,127,129,135,147, %T A215485 163,169,189,199,201,247,283,335,353,367,459,465,503,537,587,625,637, %U A215485 643,739,767,827,1009,1135,1325,1423,1433,1543,1561,1775,1781,1951,2011 %N A215485 Periods of square root continued fractions at which A013646 sets a new record. %C A215485 Each term of this sequence takes a turn at being the smallest unknown period for a square root continued fraction. Periods 1 and 2 are seen as the periods of sqrt(2) and sqrt(3) respectively, but a period of 3 is not seen until sqrt(41). %C A215485 By convention, the period for perfect squares (e.g., 1) is 0. %C A215485 Open question: Are there any more even terms after the 2? %H A215485 Patrick McKinley, <a href="/A215485/b215485.txt">Table of n, a(n) for n = 0..254</a> %e A215485 When a square root continued fraction with a period of 3 is first seen (at sqrt(41)), the lowest period not yet seen is 7, which first occurs as the period of sqrt(58). %Y A215485 Cf. A013646. %K A215485 nonn %O A215485 0,3 %A A215485 _Patrick McKinley_, Aug 12 2012