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 A131584 #5 Mar 30 2012 17:33:48 %S A131584 2,21,210,2102,21022,210220,2102203,21022039,210220396,2102203963, %T A131584 21022039638,210220396387,2102203963877,21022039638771, %U A131584 210220396387715,2102203963877155,21022039638771554,210220396387715549 %N A131584 Concatenation of first n numbers of the decimal expansion of imaginary part of 2nd nontrivial zero of Riemann zeta function. %H A131584 <a href="/index/Z#zeta_function">Index entries for zeta function</a>. %Y A131584 See A002410 and A065434 for more information. %K A131584 easy,nonn,base,less %O A131584 0,1 %A A131584 _Omar E. Pol_, Sep 13 2007