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 A212815 #7 May 30 2012 11:33:42 %S A212815 8,12,54,258280326 %N A212815 a(n) = largest number k >= 7 such that A212813(k) = n. %C A212815 Bellamy and Cadogan say that a(4) = 2*3^86093441, which is too large to include here. %D A212815 Bellamy, O. S.; Cadogan, C. C. Subsets of positive integers: their cardinality and maximality properties. Proceedings of the Tenth Southeastern Conference on Combinatorics, Graph Theory and Computing (Florida Atlantic Univ., Boca Raton, Fla., 1979), pp. 167--178, Congress. Numer., XXIII-XXIV, Utilitas Math., Winnipeg, Man., 1979. MR0561043 (82b:10006) %Y A212815 Cf. A036288, A212813, A212814, A212816, A212908, A212909. %K A212815 nonn %O A212815 0,1 %A A212815 _N. J. A. Sloane_, May 30 2012