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.

A140244 Decimal expansion of arccos(-1/4).

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%I A140244 #16 Nov 21 2024 07:47:38
%S A140244 1,8,2,3,4,7,6,5,8,1,9,3,6,9,7,5,2,7,2,7,1,6,9,7,9,1,2,8,6,3,3,4,6,2,
%T A140244 4,1,4,3,5,0,7,7,8,4,3,2,7,8,4,3,9,1,1,0,4,1,2,1,3,9,6,0,7,4,8,9,4,4,
%U A140244 8,3,2,6,3,6,2,4,1,2,5,7,2,1,7,2,5,7,6,6,1,5,4,8,9,9,0,7,3,1,3,5,5,9,6,1,6
%N A140244 Decimal expansion of arccos(-1/4).
%C A140244 Angle in radians of the obtuse angle of the obtuse scalene triangle with sides of lengths 2, 3 and 4, the scalene triangle with least integer side lengths.
%C A140244 A140240 + A140242 + A140244 = arccos(7/8) + arccos(11/16) + arccos(-1/4) = Pi.
%C A140244 Arccos(-1/4) is the least positive x for which the function f(x)=cos(x)+cos(2x) attains its minimum value, which is -9/8. - _Clark Kimberling_, Oct 28 2011
%H A140244 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>
%F A140244 arccos(-1/4) = Pi - arcsin(sqrt(15)/4) = Pi - arctan(sqrt(15)).
%e A140244 1.82347658193697527271697912863346241435077843278439110412139607489448326362...
%t A140244 RealDigits[ArcCos[-1/4],10,120][[1]] (* _Harvey P. Dale_, Dec 20 2016 *)
%o A140244 (PARI) acos(-1/4)
%Y A140244 Cf. A140239, A140240, A140241, A140242, A140243, A140245, A140246, A140247, A140248, A140249.
%K A140244 cons,nonn
%O A140244 1,2
%A A140244 _Rick L. Shepherd_, May 14 2008