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 A195103 #17 Apr 17 2018 09:41:44 %S A195103 6,6,7,6,9,1,4,5,7,1,8,9,6,0,9,1,7,6,6,5,8,6,9,0,9,2,9,3,0,0,2,4,8,4, %T A195103 8,2,2,5,1,5,9,7,8,2,9,7,4,2,9,3,7,0,9,7,7,4,9,7,9,8,6,5,7,3,2,1,7,6, %U A195103 1,6,0,8,7,8,9 %N A195103 Decimal expansion of the Dirichlet beta-function at 1/2. %C A195103 Appears in lattice sums like A088537. %H A195103 G. C. Greubel, <a href="/A195103/b195103.txt">Table of n, a(n) for n = 0..10000</a> %H A195103 Wikipedia, <a href="http://en.wikipedia.org/wiki/Dirichlet_beta_function">Dirichlet beta function</a> %F A195103 Equals (zeta(1/2,1/4) - zeta(1/2,3/4))/2 where zeta(.,.) is the Hurwitz zeta-function. %e A195103 Equals 0.66769145718960917665869... %p A195103 DirichletBeta := proc(s) (Zeta(0,s,1/4)-Zeta(0,s,3/4))/4^s ; end proc: %p A195103 x := evalf(DirichletBeta(1/2)) ; %t A195103 RealDigits[ DirichletBeta[1/2], 10, 75] // First (* _Jean-François Alcover_, Feb 20 2013, updated Mar 14 2018 *) %o A195103 (PARI) zetahurwitz(1/2,1/4)/2 - zetahurwitz(1/2,3/4)/2 \\ _Charles R Greathouse IV_, Jan 31 2018 %K A195103 nonn,cons %O A195103 0,1 %A A195103 _R. J. Mathar_, Sep 09 2011