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 A347213 #19 Aug 05 2024 13:42:33
%S A347213 2,8,4,6,9,9,0,9,7,0,0,0,7,8,2,0,7,2,1,8,7,2,1,5,3,3,2,8,1,5,7,4,7,5,
%T A347213 1,7,9,9,8,3,9,3,6,1,9,3,5,4,7,2,9,7,3,1,9,5,2,7,8,2,9,7,8,4,7,1,1,8,
%U A347213 4,5,6,7,6,1,8,9,5,1,3,9,6,4,0,2,0,0,8
%N A347213 Decimal expansion of zeta(2) + zeta(3).
%H A347213 Omran Kouba, <a href="http://www.jstor.org/stable/10.4169/math.mag.87.4.292">A zeta series</a>, Solution to Problem 1930, Mathematics Magazine, Vol. 87, No. 4 (2014), pp. 296-298.
%H A347213 Michael I. Shamos, <a href="https://citeseerx.ist.psu.edu/pdf/ae33a269baba5e8b1038e719fb3209e8a00abec5">Shamos's catalog of the real numbers</a> (2011).
%F A347213 Equals 1 + Sum_{k>=2} k * (k - Sum_{i=2..k} zeta(i)) (Kouba, 2014). - _Amiram Eldar_, Jun 09 2022
%e A347213 2.8469909700078207218721533281574751799839361...
%t A347213 RealDigits[Zeta[2] + Zeta[3], 10, 100][[1]] (* _Amiram Eldar_, Jun 09 2022 *)
%o A347213 (PARI) zeta(2)+zeta(3) \\ _Michel Marcus_, Aug 24 2021
%Y A347213 Cf. A002117, A013661, A183699.
%Y A347213 Cf. A347214, A347215, A347216, A347217, A347218, A347219, A347220.
%K A347213 nonn,cons
%O A347213 1,1
%A A347213 _Sean A. Irvine_, Aug 24 2021