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 A115389 #16 Feb 16 2025 08:33:00
%S A115389 1,1,1,3,6,5,30,105,140,126,1260,1155,13860,12870,12012,9009,72072,
%T A115389 68068,1225224,5819814,5542680,5290740,116396280,111546435,535422888,
%U A115389 514829700,1487285800,1434168450,5736673800,5545451340,166363540200,644658718275,312561802800
%N A115389 Denominator of rational part of raw moment n of the line point picking problem.
%H A115389 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/LinePointPicking.html">Line Point Picking</a>
%F A115389 a(n) = denominator of 1 + (2*n)*Sum_{k = 1..n} (-1)^(n+k+1)/k. - _Peter Bala_, Jan 05 2023
%F A115389 a(n) = denominator of 2*n*((-1)^n*log(2) - LerchPhi(-1, 1, n + 1)) + 1. - _Peter Luschny_, Jan 05 2023
%e A115389 -1 + 2*log(2), 3 - 4*log(2), -4 + 6*log(2), 17/3 - 8*log(2), -41/6 + 10*log(2), ...
%p A115389 a := n -> denom(1 + 2*n*add((-1)^(n+k+1)/k, k = 1..n)):
%p A115389 seq(a(n), n = 1..30); # _Peter Bala_, Jan 05 2023
%p A115389 # Alternative:
%p A115389 a := n -> 2*n*((-1)^n*log(2) - LerchPhi(-1, 1, n + 1)) + 1:
%p A115389 seq(denom(simplify(a(n))), n = 1..33); # _Peter Luschny_, Jan 05 2023
%Y A115389 Cf. A058312, A058313, A115388.
%K A115389 nonn,frac,easy
%O A115389 1,4
%A A115389 _Eric W. Weisstein_, Jan 21 2006