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 A327575 #5 Sep 17 2019 08:26:45
%S A327575 3,2,8,9,3,5,8,3,8,8,4,0,3,3,5,5,1,6,3,5,5,7,4,8,4,8,7,3,6,5,2,2,0,2,
%T A327575 2,9,5,7,7,0,6,6,5,2,3,7,9,4,6,9,4,0,4,4,8,0,8,4,0,3,7,9,8,7,5,2,8,1,
%U A327575 2,4,0,0,7,7,3,7,9,6,8,7,4,8,8,3,9,9,7
%N A327575 Decimal expansion of the constant that appears in the asymptotic formula for average order of an infinitary analog of Euler's phi function (A091732).
%D A327575 Steven R. Finch, Mathematical Constants II, Cambridge University Press, 2018, section 1.7.5, pp. 53-54.
%H A327575 Graeme L. Cohen and Peter Hagis, Jr., <a href="http://dx.doi.org/10.1155/S0161171293000456">Arithmetic functions associated with infinitary divisors of an integer</a>, International Journal of Mathematics and Mathematical Sciences, Vol. 16, No. 2 (1993), pp. 373-383.
%F A327575 Equals Limit_{k->oo} A327572(k)/k^2.
%F A327575 Equals (1/2) * Product_{P} (1 - 1/(P*(P+1))), where P are numbers of the form p^(2^k) where p is prime and k >= 0 (A050376).
%e A327575 0.328935838840335516355748487365220229577066523794694...
%t A327575 $MaxExtraPrecision = 1500; m = 1500; em = 10; f[x_] := Sum[Log[1 - x^(2^e)/(1 + 1/x^(2^e))], {e, 0, em}]; c = Rest[CoefficientList[Series[f[x], {x, 0, m}], x]*Range[0, m]]; RealDigits[(1/2) * Exp[NSum[Indexed[c, k]*PrimeZetaP[k]/k, {k, 2, m}, NSumTerms -> m, WorkingPrecision -> m]], 10, 100][[1]]
%Y A327575 Cf. A091732, A050376, A327572.
%Y A327575 Cf. A104141 (corresponding constant for phi), A065463 (unitary), A306071 (bi-unitary).
%K A327575 nonn,cons
%O A327575 0,1
%A A327575 _Amiram Eldar_, Sep 17 2019