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 A195572 #11 Jun 13 2025 18:36:55 %S A195572 0,9,11,20,819,1221,2020,83629,124431,206040,8529239,12690841, %T A195572 21014040,869898849,1294341251,2143226060,88721153259,132010116861, %U A195572 218588044060,9048687733669,13463737578471,22293837268080,922877427680879 %N A195572 Numerators b(n) of Pythagorean approximations b(n)/a(n) to 1/5. %C A195572 See A195500 for discussion and list of related sequences; see A195571 for Mathematica program. %C A195572 Conjecture: satisfies a linear recurrence having signature (0, 0, 101, 0, 0, 101, 0, 0, -1). - _Harvey P. Dale_, Jun 13 2025 %F A195572 Empirical g.f.: -x^2*(x^7-x^6-110*x^4+90*x^3-20*x^2-11*x-9) / (x^9-101*x^6-101*x^3+1). - _Colin Barker_, Jun 04 2015 %Y A195572 Cf. A195500, A195571, A195573. %K A195572 nonn %O A195572 1,2 %A A195572 _Clark Kimberling_, Sep 21 2011