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 A158507 #5 Mar 16 2014 15:14:18
%S A158507 1,-3,-11,15,599,-395,-3893,20855,1297199,-1869111,-315196855,
%T A158507 255365275,304261665587,-49453295827,-1056627547637,12890470331775,
%U A158507 26749039258693183,-4351895477983343,-2270808628615272191,1847319496652416355,3100305824682616298389
%N A158507 Numerator of Bernoulli(n, 2/7).
%H A158507 Vincenzo Librandi, <a href="/A158507/b158507.txt">Table of n, a(n) for n = 0..250</a>
%t A158507 Table[Numerator[BernoulliB[n, 2/7]], {n, 0, 50}] (* _Vincenzo Librandi_, Mar 16 2014 *)
%Y A158507 For denominators see A158475.
%K A158507 sign,frac
%O A158507 0,2
%A A158507 _N. J. A. Sloane_, Nov 08 2009