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 A195557 #12 Jun 04 2015 14:28:12 %S A195557 0,5,7,12,155,301,444,5921,11395,16872,224807,432745,640680,8536781, %T A195557 16432879,24328980,324172835,624016693,923860548,12310030985, %U A195557 23696201419,35082371856,467457004559,899831637265,1332206269968,17751056142293 %N A195557 Numerators b(n) of Pythagorean approximations b(n)/a(n) to 1/3. %C A195557 See A195500 for discussion and list of related sequences; see A195556 for Mathematica program. %F A195557 Conjecture: a(n) = +37*a(n-3) +37*a(n-6) -a(n-9). - _R. J. Mathar_, Sep 21 2011 %F A195557 Empirical g.f.: -x^2*(x^7-x^6-42*x^4+30*x^3-12*x^2-7*x-5) / (x^9-37*x^6-37*x^3+1). - _Colin Barker_, Jun 04 2015 %Y A195557 Cf. A195500, A195556, A195558. %K A195557 nonn %O A195557 1,2 %A A195557 _Clark Kimberling_, Sep 21 2011