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 A195403 #10 Jul 18 2021 09:53:56 %S A195403 6,9,2,0,2,8,6,7,8,4,7,1,6,5,1,7,6,7,9,0,4,3,2,8,7,4,5,2,5,6,2,9,3,2, %T A195403 5,2,0,0,9,4,0,2,2,7,5,9,3,1,3,3,3,2,2,7,0,3,7,6,1,6,4,8,0,3,3,1,9,2, %U A195403 5,7,7,4,5,6,5,6,6,8,8,7,5,7,5,3,6,4,5,9,7,8,4,0,1,8,6,1,7,5,7,8,9 %N A195403 Decimal expansion of shortest length, (A), of segment from side AB through incenter to side AC in right triangle ABC with sidelengths (a,b,c)=(1,sqrt(r),r), where r=(1+sqrt(5))/2 (the golden ratio). %C A195403 See A195284 for definitions and a general discussion. %e A195403 (A)=0.69202867847165176790432874525629325200... %t A195403 a = 1; b = Sqrt[c]; c = (1 + Sqrt[5])/2; %t A195403 f = 2 a*b/(a + b + c); %t A195403 x1 = Simplify[f*Sqrt[a^2 + (b + c)^2]/(b + c) ] %t A195403 x2 = Simplify[f*Sqrt[b^2 + (c + a)^2]/(c + a) ] %t A195403 x3 = f*Sqrt[2] %t A195403 N[x1, 100] %t A195403 RealDigits[%] (* (A) A195403 *) %t A195403 N[x2, 100] %t A195403 RealDigits[%] (* (B) A195404 *) %t A195403 N[x3, 100] %t A195403 RealDigits[%] (* (C) A195405 *) %t A195403 N[(x1 + x2 + x3)/(a + b + c), 100] %t A195403 RealDigits[%] (* Philo(ABC,I) A195406 *) %Y A195403 Cf. A195284, A195404, A195405, A195406. %K A195403 nonn,cons %O A195403 0,1 %A A195403 _Clark Kimberling_, Sep 17 2011 %E A195403 a(99) corrected by _Georg Fischer_, Jul 18 2021