cp's OEIS Frontend

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.

A327574 Decimal expansion of the constant that appears in the asymptotic formula for average order of the infinitary divisors sum function (A049417).

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%I A327574 #8 Jun 13 2020 07:58:14
%S A327574 7,3,0,7,1,8,2,4,2,1,2,7,3,8,4,2,2,5,8,3,8,9,7,5,4,6,8,1,7,3,5,3,0,1,
%T A327574 6,1,9,5,7,2,5,6,4,3,3,8,6,1,7,2,7,8,6,9,7,0,7,3,3,6,7,6,2,3,0,1,0,7,
%U A327574 9,8,8,3,3,2,8,0,0,5,3,4,6,3,7,0,2,9,9
%N A327574 Decimal expansion of the constant that appears in the asymptotic formula for average order of the infinitary divisors sum function (A049417).
%C A327574 The asymptotic mean of the infinitary abundancy index lim_{n->oo} (1/n) * Sum_{k=1..n} A049417(k)/k = 1.461436... is twice this constant. - _Amiram Eldar_, Jun 13 2020
%D A327574 Steven R. Finch, Mathematical Constants II, Cambridge University Press, 2018, section 1.7.5, pp. 53-54.
%H A327574 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 A327574 Equals Limit_{k->oo} A327566(k)/k^2.
%F A327574 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 A327574 0.730718242127384225838975468173530161957256433861727...
%t A327574 $MaxExtraPrecision = 1000; m = 1000; 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 A327574 Cf. A049417, A050376, A327566.
%Y A327574 Cf. A013661 (corresponding constant for all divisors), A275480 (exponential), A306633 (unitary), A307160 (bi-unitary).
%K A327574 nonn,cons
%O A327574 0,1
%A A327574 _Amiram Eldar_, Sep 17 2019