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%I #13 Jan 17 2020 03:43:34
%S 5,4,8,3,0,0,8,3,1,2,8,2,0,9,8,4,0,7,6,7,7,6,4,0,4,9,1,5,2,2,6,7,3,1,
%T 5,4,4,9,7,0,1,9,9,4,6,1,0,0,1,8,5,0,9,9,4,5,1,3,7,3,8,5,9,2,8,5,7,9,
%U 7,7,4,2,6,6,3,7,4,1,6,2,1,7,2,4,5,4,9,6,4,3,0,1,2,2,2,6,9,3,1,9,6,3,2
%N Decimal expansion of product_{p=primes} (1-1/(2^p-1)).
%H Steven R. Finch, <a href="http://arxiv.org/abs/2001.00578">Errata and Addenda to Mathematical Constants</a>, p. 17.
%F Equals product_{p in A000040} (1-1/(2^p-1)) = product_{n>=1} (1-1/A001348(n)).
%e (1-1/3) *(1-1/7) *(1-1/31) *(1-1/127) *(1-1/2047) * ... = 0.5483008312820984076776404...
%t digits = 103; m0 = 10; dm = 10; f[m_] := f[m] = Product[p = Prime[n]; 1 - 1/(2^p - 1), {n, 1, m}]; f[m0]; f[m = m0 + dm]; While[RealDigits[f[m], 10, digits+2] != RealDigits[f[m - dm], 10, digits+2], m = m + dm]; RealDigits[f[m], 10, digits] // First (* _Jean-François Alcover_, Oct 14 2014 *)
%K cons,nonn
%O 0,1
%A _R. J. Mathar_, Jan 09 2011
%E More digits from _Jean-François Alcover_, Oct 14 2014
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