login

Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.

Decimal expansion of 3*sqrt(15)/2.
12

%I #15 Oct 30 2023 09:51:03

%S 5,8,0,9,4,7,5,0,1,9,3,1,1,1,2,5,3,2,7,7,6,8,8,9,8,0,9,9,6,7,3,5,9,9,

%T 4,1,6,2,4,9,3,8,2,5,5,7,9,3,7,3,8,6,2,3,9,8,8,1,3,6,0,6,4,9,1,7,0,2,

%U 2,4,6,3,7,9,0,5,4,6,8,5,5,0,2,7,8,9,3,1,0,6,5,2,8,8,0,1,0,2,7,6,8,7,4,4,5

%N Decimal expansion of 3*sqrt(15)/2.

%C Exradius opposite the side of length 4 of the obtuse scalene triangle with sides of lengths 2, 3 and 4, the scalene triangle with least integer side lengths. See formulas in the Weisstein link.

%H Daniel Starodubtsev, <a href="/A140249/b140249.txt">Table of n, a(n) for n = 1..10000</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Exradius.html">Exradius</a>.

%H <a href="/index/Al#algebraic_02">Index entries for algebraic numbers, degree 2</a>

%F 3*sqrt(15)/2 = 3*A010472/2 = 2*A140239 = 3*A088543 = 5*A140248.

%e 5.80947501931112532776889809967359941624938255793738623988136064917022463790...

%t First[RealDigits[3 Sqrt[15]/2,10,100]] (* _Paolo Xausa_, Oct 30 2023 *)

%o (PARI) 3*sqrt(15)/2

%Y Cf. A140239, A140240, A140241, A140242, A140243, A140244, A140245, A140246, A140247, A140248, A088543, A010472.

%K cons,nonn

%O 1,1

%A _Rick L. Shepherd_, May 14 2008