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 A195409 #10 Jul 18 2021 10:02:11 %S A195409 7,1,2,7,8,7,9,1,7,3,8,5,2,0,1,2,3,3,8,0,1,6,0,9,4,6,9,7,2,6,8,2,7,1, %T A195409 4,1,7,5,3,6,0,7,6,5,8,6,6,8,5,4,6,6,9,8,4,2,4,8,1,2,2,8,5,5,4,1,6,3, %U A195409 4,0,6,1,1,8,1,9,2,3,1,9,4,8,0,4,3,8,8,6,7,5,2,7,4,6,6,0,0,6,0,3,6,8,7,5 %N A195409 Decimal expansion of shortest length, (C), of segment from side CA through incenter to side CB in right triangle ABC with sidelengths (a,b,c)=(r-1,r,sqrt(3)), where r=(1+sqrt(5))/2 (the golden ratio). %C A195409 See A195284 for definitions and a general discussion. %e A195409 (C)=0.71278791738520123380160946972682714175360765866... %t A195409 a = b - 1; b = (1 + Sqrt[5])/2; c = Sqrt[3]; %t A195409 f = 2 a*b/(a + b + c); %t A195409 x1 = Simplify[f*Sqrt[a^2 + (b + c)^2]/(b + c) ] %t A195409 x2 = Simplify[f*Sqrt[b^2 + (c + a)^2]/(c + a) ] %t A195409 x3 = f*Sqrt[2] %t A195409 N[x1, 100] %t A195409 RealDigits[%] (* (A) A195407 *) %t A195409 N[x2, 100] %t A195409 RealDigits[%] (* (B) A195408 *) %t A195409 N[x3, 100] %t A195409 RealDigits[%] (* (C) A195409 *) %t A195409 N[(x1 + x2 + x3)/(a + b + c), 100] %t A195409 RealDigits[%] (* Philo(ABC,I) A195410 *) %Y A195409 Cf. A195284. %K A195409 nonn,cons %O A195409 0,1 %A A195409 _Clark Kimberling_, Sep 17 2011 %E A195409 a(99) corrected by _Georg Fischer_, Jul 18 2021