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 A343143 Decimal expansion of the angle in radians at the apex of the Calabi triangle. 0
 1, 7, 7, 5, 6, 2, 7, 2, 5, 5, 2, 6, 9, 6, 2, 9, 8, 6, 2, 5, 0, 8, 4, 8, 1, 6, 7, 2, 0, 2, 8, 7, 2, 8, 5, 4, 2, 6, 9, 5, 0, 9, 1, 7, 6, 5, 5, 6, 8, 6, 6, 9, 3, 4, 4, 7, 9, 2, 3, 8, 1, 4, 1, 9, 8, 1, 0, 3, 1, 5, 2, 6, 5, 9, 8, 5, 3, 3, 9, 9, 9, 7, 9, 2, 0, 1, 3 (list; constant; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS The angle in degrees is 101.7359477153... and each of the base angles is 0.6829826991... radians or 39.1320261423... degrees. REFERENCES John H. Conway and Richard K. Guy, The Book of Numbers, Copernicus (Springer-Verlag), 1996, p. 206. Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, section 8.13, pp. 523-524. LINKS Eugenio Calabi, Outline of Proof Regarding Squares Wedged in Triangle, 1997. Eric Weisstein's World of Mathematics, Calabi's Triangle. Wikipedia, Calabi triangle. FORMULA Equals 2*arcsin(c/2), where c = A046095. EXAMPLE 1.77562725526962986250848167202872854269509176556866... MATHEMATICA r = x /. FindRoot[2 x^3 - 2 x^2 - 3 x + 2 == 0, {x, 1.5}, WorkingPrecision -> 200]; RealDigits[2*ArcSin[r/2], 10, 100][[1]] CROSSREFS Cf. A046095. Sequence in context: A336078 A074917 A154016 * A220781 A198566 A154193 Adjacent sequences:  A343139 A343141 A343142 * A343144 A343145 A343146 KEYWORD nonn,cons AUTHOR Amiram Eldar, Jun 18 2021 STATUS approved

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Last modified July 27 10:31 EDT 2021. Contains 346304 sequences. (Running on oeis4.)