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 A152623 #23 Apr 29 2024 09:37:36 %S A152623 1,5,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, %T A152623 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, %U A152623 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 %N A152623 Decimal expansion of 3/2. %C A152623 Sum of the inverses of the tetrahedral numbers (A000292). - _Michael B. Porter_, Nov 27 2017 %C A152623 For any triangle ABC, cos A + cos B + cos C <= 3/2; equality is obtained only when the triangle is equilateral (see the Kiran S. Kedlaya link). - _Bernard Schott_, Sep 17 2022 %H A152623 Kiran S. Kedlaya, <a href="https://igor-kortchemski.perso.math.cnrs.fr/olympiades/Cours/ineqs-080299.pdf">A < B</a>, (1999), Problem 6.2, p. 6. %H A152623 <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (1). %e A152623 1.5000000000000000000000000000000000000000000000000000000000... %o A152623 (PARI) 3/2. \\ _Charles R Greathouse IV_, Jan 10 2022 %Y A152623 Cf. A000292 (tetrahedral numbers). %Y A152623 Sums of inverses: A002117 (cubes), A175577 (octahedral numbers), A295421 (dodecahedral numbers), A175578 (icosahedral numbers). %Y A152623 Cf. A002194, A020821, A104956 (other trigonometric inequalities). %K A152623 nonn,cons,easy %O A152623 1,2 %A A152623 _N. J. A. Sloane_, Oct 30 2009