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 A052469 Denominators in the Taylor series for arccosh(x) - log(2x). 4
 4, 32, 96, 1024, 2560, 4096, 28672, 524288, 1179648, 5242880, 11534336, 100663296, 218103808, 939524096, 134217728, 68719476736, 146028888064, 206158430208, 1305670057984, 2199023255552, 7696581394432, 96757023244288, 202310139510784, 1125899906842624 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 REFERENCES Bronstein-Semendjajew, sprawotchnik po matematikje, 6th Russian ed. 1956, ch. 4.2.6. LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 Eric Weisstein's World of Mathematics, Inverse Hyperbolic Cosecant Eric Weisstein's World of Mathematics, Inverse Hyperbolic Cosine Eric Weisstein's World of Mathematics, Inverse Hyperbolic Sine FORMULA A052468(n) / a(n) = A001147(n) / ( A000165(n) *2*n ) From Johannes W. Meijer, Jul 06 2009: (Start) a(n) = denom((2*n-1)!/( 2^(2*n)* (n!)^2)). Equals 2*A162442(n+1) for n >= 1. A052468(n)/a(n) = (1/(2*n))*A001790(n)/A046161(n) for n>=1. (End) EXAMPLE arccosh(x) = log(2x) - 1/(4*x^2) - 3/(32*x^4) - 5/(96*x^6) - ... for x>1. MATHEMATICA a[n_] := Denominator[(2*n-1)!/(2^(2*n)*n!^2)]; Array[a, 21] (* Jean-François Alcover, May 17 2017 *) PROG (MAGMA) [Denominator(Factorial(2*n-1)/( 2^(2*n)* Factorial(n)^2)): n in [1..30]]; // Vincenzo Librandi, Jul 10 2017 CROSSREFS Cf. A002595. Sequence in context: A153794 A222326 A108914 * A211625 A211630 A211626 Adjacent sequences:  A052466 A052467 A052468 * A052470 A052471 A052472 KEYWORD nonn,easy,frac AUTHOR EXTENSIONS Updated by Frank Ellermann, May 22 2001 STATUS approved

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Last modified August 20 18:42 EDT 2017. Contains 290837 sequences.