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 A383267 #29 May 23 2025 02:12:38 %S A383267 7,1,3,7,6,5,8,5,5,5,0,3,6,0,8,1,7,0,6,7,1,8,9,9,9,9,1,7,6,2,6,6,1,2, %T A383267 4,7,5,9,0,7,9,6,5,4,7,5,8,9,0,3,8,0,6,6,9,1,5,6,2,6,7,5,2,0,8,4,5,8, %U A383267 3,1,4,7,0,6,7,7,1,8,7,5,6,4,6,3,2,4,0,3,3,9,9,3,2,2,6,8,1,7,1,7,2,4,4,6,4 %N A383267 Decimal expansion of (4/11)^(1/3). %C A383267 In the standard cosmology, the temperature of the free-streaming neutrinos which formed the cosmic neutrino background is (4/11)^(1/3) of the relic photon temperature after the electron-positron annihilation in the early universe (assuming that all electrons and positrons annihilated into photons). %D A383267 E. W. Kolb and M. S. Turner, The Early Universe, Addison-Wesley, Redwood City, CA, 1990, p. 503 Appendix A. %D A383267 R. E. Lopez, S. Dodelson, A. Heckler and M. S. Turner, Precision detection of the cosmic neutrino background, Physical Review Letters 82 (1999) 3952-3955, p. 3952. %D A383267 Steven Weinberg, Gravitation and Cosmology Principles and Applications of the General Theory of Relativity, John Wiley, New York, 1972, p. 537. %H A383267 Wikipedia, <a href="http://en.wikipedia.org/wiki/Cosmic_neutrino_background">Cosmic neutrino background</a>. %F A383267 Equals 1/A111728 = A005480/A010583. %e A383267 0.713765855503608170671899991762661247590796547589038066915626752084583... %t A383267 RealDigits[(4/11)^(1/3),10,105][[1]] (* _Stefano Spezia_, Apr 25 2025 *) %o A383267 (Magma) SetDefaultRealField(RealField(106)); n:=(4/11)^(1/3); Reverse(Intseq(Floor(10^105*n))); %o A383267 (PARI) (4/11)^(1/3) %Y A383267 Cf. A111728. %K A383267 nonn,cons,easy %O A383267 0,1 %A A383267 _Arkadiusz Wesolowski_, Apr 21 2025