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 A086730 #11 Jul 19 2013 18:03:44 %S A086730 0,8,5,1,0,7,6,5,0,2,5,9,9,6,4,3,7,2,4,9,9,6,4,7,7,0,0,9,2,4,3,2,4,5, %T A086730 8,7,5,8,9,7,9,7,0,8,5,8,4,3,7,0,5,8,1,5,5,5,3,9,6,6,1,8,4,2,8,1,3,6, %U A086730 2,1,7,9,1,8,5,5,7,0,0,4,2,0,5,3,2,3,8,9,5,9,2,7,0,3,9,1,4,0,1 %N A086730 Decimal expansion of sum(1/(6*m+4)^2,m=0..infinity). %D A086730 L. Fejes Toth, Lagerungen in der Ebene, auf der Kugel und im Raum, 2nd. ed., Springer-Verlag, Berlin, Heidelberg 1972; see p. 213. %F A086730 .085107650259964... = Psi'(2/3)/36 where Psi'(x) denotes the first derivative of the digamma function - R. Piyo (nagoya314(AT)yahoo.com), Dec 12 2004 %F A086730 8*Zeta(2)/9 = A214550 +4*(this constant) with Zeta(2) = A013661. - _R. J. Mathar_, Sep 15 2012 %e A086730 0.085107650259964... %t A086730 RealDigits[ PolyGamma[1, 2/3]/36, 10, 98] // First // Prepend[#, 0]& (* _Jean-François Alcover_, Feb 12 2013 *) %o A086730 (PARI) psi'(2/3)/36 \\ _Charles R Greathouse IV_, Jul 19 2013 %Y A086730 Cf. A086722-A086731. %K A086730 nonn,cons %O A086730 0,2 %A A086730 _N. J. A. Sloane_, Jul 31 2003