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 A073747 #47 Feb 16 2025 08:32:46 %S A073747 1,3,1,3,0,3,5,2,8,5,4,9,9,3,3,1,3,0,3,6,3,6,1,6,1,2,4,6,9,3,0,8,4,7, %T A073747 8,3,2,9,1,2,0,1,3,9,4,1,2,4,0,4,5,2,6,5,5,5,4,3,1,5,2,9,6,7,5,6,7,0, %U A073747 8,4,2,7,0,4,6,1,8,7,4,3,8,2,6,7,4,6,7,9,2,4,1,4,8,0,8,5,6,3,0,2,9,4,6,7,9 %N A073747 Decimal expansion of coth(1). %C A073747 coth(x) = (e^x + e^(-x))/(e^x - e^(-x)). %C A073747 Because the continued fraction for coth(1) is all positive odd numbers in sequence, the second Mathematica program below also generates the sequence. - _Harvey P. Dale_, Oct 15 2011 %C A073747 By the Lindemann-Weierstrass theorem, this constant is transcendental. - _Charles R Greathouse IV_, May 14 2019 %D A073747 Samuel M. Selby, editor, CRC Basic Mathematical Tables, CRC Press, 1970, p. 218. %H A073747 Ivan Panchenko, <a href="/A073747/b073747.txt">Table of n, a(n) for n = 1..1000</a> %H A073747 Hideyuki Ohtsuka, <a href="http://www.jstor.org/stable/10.4169/amer.math.monthly.122.7.700">Problem 11853</a>, The American Mathematical Monthly, Vol. 122, No. 7 (2015), p. 700; <a href="https://www.jstor.org/stable/10.4169/amer.math.monthly.124.5.465">A Hyperbolic Sine Series</a>, Solutions to Problem 11853 by Tewodros Amdeberhan and Rituraj Nandan, ibid., Vol. 124, No. 5 (2017), p. 469. %H A073747 Allen Stenger, <a href="https://www.jstor.org/stable/10.4169/amer.math.monthly.124.2.116">Experimental math for Math Monthly problems</a>, The American Mathematical Monthly, Vol. 124, No. 2 (2017), pp. 116-131; <a href="https://www.allenstenger.com/uploads/1/4/1/8/14182140/expmathmathmonthlyfeb2017.pdf">alternative link</a>. %H A073747 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/HyperbolicCotangent.html">Hyperbolic Cotangent</a>. %H A073747 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/HyperbolicFunctions.html">Hyperbolic Functions</a>. %H A073747 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a> %F A073747 Equals 1 + Sum_{n>=1} (2^(2*n)*B(2*n))/(2*n)! = 1 + Sum_{n>=1} (-1)^(n+1)*2*(A046988(n+1) / A002432(n+1)). - _Terry D. Grant_, May 30 2017 %F A073747 Equals 1 + BesselI(3/2, 1)/BesselI(1/2, 1). - _Terry D. Grant_, Jun 18 2018 %F A073747 Equals 1 + Sum_{k>=1} csch(2^k) (Ohtsuka, 2015; Stenger, 2017). - _Amiram Eldar_, Oct 04 2021 %e A073747 1.31303528549933130363616124693... %t A073747 RealDigits[Coth[1],10,120][[1]] (* or *) RealDigits[ FromContinuedFraction[ Range[1,1001,2]],10,120][[1]] (* _Harvey P. Dale_, Oct 15 2011 *) (* see Comments, above, for the second program *) %o A073747 (PARI) 1/tanh(1) %Y A073747 Cf. A005408 (continued fraction: odd numbers), A073821 (continued fraction exp. is even numbers), A073744 (tanh(1)=1/A073747), A073742 (sinh(1)), A073743 (cosh(1)), A073745 (csch(1)), A073746 (sech(1)), A349004. %K A073747 cons,nonn %O A073747 1,2 %A A073747 _Rick L. Shepherd_, Aug 07 2002