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 A264736 #47 Feb 16 2025 08:33:27
%S A264736 5,7,3,8,1,3,8,6,2,6,1,2,0,7,0,5,9,9,0,4,7,8,8,6,3,9,3,4,5,7,9,0,6,3,
%T A264736 2,7,6,6,4,7,7,6,1,0,9,5,5,8,6,8,7,3,8,6,2,4,8,7,0,9,3,8,7,1,4,6,2,2,
%U A264736 4,3,8,8,5,7,6,7,0,1,3,6,8,1,9,2,8,5,4,5,7,7,5,2,8,5,2,0,6,3,0
%N A264736 Decimal expansion of Product_{p prime > 2} 1-1/(p^2-3p+3), a constant related to I. M. Vinogradov's proof of the "ternary" Goldbach conjecture.
%D A264736 Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 2.1 Hardy-Littlewood Constants, p. 88.
%H A264736 Eric Weisstein's MathWorld, <a href="https://mathworld.wolfram.com/GoldbachConjecture.html">Goldbach's Conjecture</a>.
%H A264736 Eric Weisstein's MathWorld, <a href="https://mathworld.wolfram.com/VinogradovsTheorem.html">Vinogradov's theorem</a>.
%H A264736 Wikipedia, <a href="http://en.wikipedia.org/wiki/Goldbach%27s_conjecture">Goldbach's conjecture</a>.
%H A264736 Wikipedia, <a href="https://en.wikipedia.org/wiki/Vinogradov's_theorem">Vinogradov's theorem</a>.
%F A264736 Equals A005597 / A271951.
%e A264736 0.5738138626120705990478863934579063276647761095586873862487...
%t A264736 $MaxExtraPrecision = 600; digits = 99; terms = 600; P[n_] := PrimeZetaP[n] - 1/2^n; LR = LinearRecurrence[{6, -14, 15, -6}, {0, 0, -2, -9}, terms + 10]; r[n_Integer] := LR[[n]]; Exp[NSum[r[n]*P[n-1]/(n-1), {n, 3, terms}, NSumTerms -> terms, WorkingPrecision -> digits+10]] // RealDigits[#, 10, digits]& // First
%o A264736 (PARI) prodeulerrat(1-1/(p^2-3*p+3), 1, 3) \\ _Amiram Eldar_, Mar 11 2021
%Y A264736 Cf. A005597, A271951.
%K A264736 nonn,cons
%O A264736 0,1
%A A264736 _Jean-François Alcover_, Apr 17 2016