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 A262276 #64 May 30 2025 03:32:21
%S A262276 9,5,5,9,2,3,0,1,5,8,6,1,9,0,2,3,7,6,8,8,4,0,6,5,3,8,6,7,0,9,8,7,0,0,
%T A262276 7,4,6,7,7,1,5,9,4,3,1,6,5,4,5,6,8,6,8,8,3,2,8,0,5,8,9,4,9,0,1,8,1,7,
%U A262276 2,8,7,0,1,5,5,2,2,9,2,5,7,1,0,3,5,7,2,0,0,5,5,9,1,1,6,4,4,0,3,5,2,3,0,1,2,9,3,3,4,7,1,7,1,5,8,0,1,2,2,4,3,6,3,9,8,9,3,3,8,8,1,2,0,3,8,6,6,0,1,3,2,8,6,3,2,6,7,5,2,0,6,6,3,5,8,0,2,7,1,7,9,6,0
%N A262276 Decimal expansion of Toth's constant (the density of the exponentially squarefree numbers).
%H A262276 Vladimir Shevelev, <a href="http://arxiv.org/abs/1602.04244">A fast computation of density of exponentially S-numbers</a>, arXiv:1602.04244 [math.NT], 2016.
%H A262276 László Tóth, <a href="https://ac.inf.elte.hu/Vol_027_2007/doi/155_27.pdf">On certain arithmetic functions involving exponential divisors, II.</a>, Annales Univ. Sci. Budapest., Sect. Comp., 27 (2007), 155-166.
%F A262276 Equals Product_{prime p} (1+Sum_{j>=4} (mu(j)^2 - mu(j-1)^2)/p^j), where mu(n) is the Möbius function.
%e A262276 0.95592301586190237688406538670987007467715943165456868832805...
%t A262276 $MaxExtraPrecision = m = 1000; f[x_] := Log[1 - x^4 + (1 - x)*Sum[x^e*(MoebiusMu[e]^2), {e, 4, m}]]; c = Rest[CoefficientList[Series[f[x], {x, 0, m}], x]*Range[0, m]]; RealDigits[Exp[NSum[Indexed[c, k]*PrimeZetaP[k]/k, {k, 2, m}, NSumTerms -> m, WorkingPrecision -> m]], 10, 163][[1]] (* _Amiram Eldar_, Apr 27 2025 *)
%Y A262276 Density of A209061.
%Y A262276 Cf. A008683.
%K A262276 nonn,cons
%O A262276 0,1
%A A262276 _Juan Arias-de-Reyna_, Sep 19 2015