cp's OEIS Frontend

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.

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).

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%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