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 A157239 #2 Mar 30 2012 16:51:17 %S A157239 1,-1,-195,587,190905,-958441,-456423435,3208393187,2031120835185, %T A157239 -18357153435601,-14521552284155475,160410736104452987, %U A157239 152266846748812455465,-1987817374606532447161,-2201371244223771530940315,33159832798775207321651987,41968251293767181816904683745 %N A157239 Numerator of Euler(n, 13/28). %Y A157239 For denominators see A009972. %K A157239 sign,frac %O A157239 0,3 %A A157239 _N. J. A. Sloane_, Nov 07 2009