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 A256847 #13 Sep 08 2022 08:46:12 %S A256847 2,0,2,2,6,9,6,7,4,0,5,4,5,8,9,4,3,9,5,5,6,9,8,8,0,3,8,2,0,8,4,8,7,6, %T A256847 7,6,2,7,7,2,1,0,2,3,3,1,9,5,1,4,6,7,2,7,3,5,8,8,9,8,1,9,6,0,2,5,4,7, %U A256847 9,8,7,9,2,9,0,4,3,1,1,9,0,0,6,8,6,9,4,8,9,7,6,7,5,2,7,2,6,5,6,3,9,2,3,4 %N A256847 Decimal expansion of the generalized Euler constant gamma(4,4) (negated). %H A256847 G. C. Greubel, <a href="/A256847/b256847.txt">Table of n, a(n) for n = 0..10000</a> %H A256847 D. H. Lehmer, <a href="http://matwbn.icm.edu.pl/ksiazki/aa/aa27/aa27121.pdf">Euler constants for arithmetic progressions</a>, Acta Arith. 27 (1975) p. 134. %F A256847 Equals (EulerGamma - log(4))/4. %e A256847 -0.202269674054589439556988038208487676277210233195146727358898... %t A256847 RealDigits[EulerGamma/4 - Log[4]/4, 10, 104] // First %o A256847 (PARI) default(realprecision, 100); (Euler - log(4))/4 \\ _G. C. Greubel_, Aug 28 2018 %o A256847 (Magma) SetDefaultRealField(RealField(100)); R:= RealField(); (EulerGamma(R) - Log(4))/4; // _G. C. Greubel_, Aug 28 2018 %Y A256847 Cf. A001620 (gamma(1,1) = EulerGamma), %Y A256847 Primitive ruler-and-compass constructible gamma(r,k): A228725 (1,2), A256425 (1,3), A256778 (1,4), A256779 (1,5), A256780 (2,5), A256781 (1,8), A256782 (3,8), A256783 (1,12), A256784 (5,12), %Y A256847 Other gamma(r,k) (1 <= r <= k <= 5): A239097 (2,2), A256843 (2,3), A256844 (3,3), A256845 (2,4), A256846 (3,4), A256847 (4,4), A256848 (3,5), A256849 (4,5), A256850 (5,5). %K A256847 nonn,cons,easy %O A256847 0,1 %A A256847 _Jean-François Alcover_, Apr 11 2015