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 A030125 #56 Feb 16 2025 08:32:35
%S A030125 5,9,2,6,3,2,7,1,8,2,0,1,6,3,6,1,9,7,1,0,4,0,7,8,6,0,4,9,9,5,7,0,1,4,
%T A030125 6,9,0,8,4,2,7,5,4,0,7,1,9,7,1,6,1,0,7,1,0,9,9,5,6,2,6,0,8,1,5,8,2,4,
%U A030125 7,3,5,2,3,6,4,1,6,0,0,0,8,5,1,0,6,6,4,7,8,4,2,9,7,1,0,1,2,5,7,0,5,1,1,8
%N A030125 Decimal expansion of Lehmer's constant.
%C A030125 Digits 999 and 1000 should be "48" not "65" as given in the Plouffe links. - _Sean A. Irvine_, Aug 24 2014
%C A030125 Named after the American mathematician Derrick Henry Lehmer (1905-1991). - _Amiram Eldar_, Jun 22 2021
%D A030125 Steven R. Finch, Mathematical Constants, Cambridge, 2003, pp. 433-434.
%H A030125 Simon Plouffe and Sean A. Irvine, <a href="/A030125/b030125.txt">Table of n, a(n) for n = 0..2000</a> [Replaces terms 0..998 from Harry J. Smith.]
%H A030125 Steven R. Finch, <a href="http://www.people.fas.harvard.edu/~sfinch/constant/lehmer/lehmer.html">Lehmer's Constant</a>. [Broken link]
%H A030125 Steven R. Finch, <a href="http://web.archive.org/web/20010603070928/http://www.mathsoft.com/asolve/constant/lehmer/lehmer.html">Lehmer's Constant</a>. [From the Wayback machine]
%H A030125 D. H. Lehmer, <a href="/A002065/a002065_1.pdf">A cotangent analogue of continued fractions</a>, Duke Math. J., Vol. 4, No. 2 (1938), pp. 323-340. [Annotated scanned copy]
%H A030125 Simon Plouffe, <a href="http://www.worldwideschool.org/library/books/sci/math/MiscellaneousMathematicalConstants/chap52.html">The Lehmer Constant to 1000 digits</a>.
%H A030125 Simon Plouffe, <a href="http://www.plouffe.fr/simon/constants/lehmer.txt">The Lehmer constant to 1000 digits</a>.
%H A030125 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/LehmersConstant.html">Lehmer's Constant</a>.
%F A030125 Equals cot(Sum_{k>=0} (-1)^k * arccot(A002065(k))). - _Amiram Eldar_, Aug 18 2020
%e A030125 0.592632718201636197104078604995701469084275407197161...
%t A030125 RealDigits[With[{nn=15},Cot[Total[Last[#]ArcCot[First[#]]&/@Thread[ {NestList[ #^2+#+1&,0,nn],PadRight[{},nn+1,{1,-1}]}]]]],10,120][[1]] (* _Harvey P. Dale_, Jan 29 2012 *)
%o A030125 (PARI) b=0.;1/tan(suminf(k=1,b=b^2+b+1;(-1)^k*atan(1/b))+Pi/2) \\ _Charles R Greathouse IV_, Jan 21 2016
%Y A030125 Cf. A002065, A002794, A002795, A030125.
%Y A030125 Cf. A002665 (continued fraction). - _Harry J. Smith_, May 14 2009
%K A030125 nonn,cons,nice
%O A030125 0,1
%A A030125 _Eric W. Weisstein_
%E A030125 More terms from _David W. Wilson_