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 A216139 #7 Oct 03 2012 14:59:53 %S A216139 3674,2385,1836,1608,1438,1333,1239,1201,3,1040,1001,978,980,948,929, %T A216139 881,914,852,3,828,818,834,820,819,779,786,762,750,3,708,753,759,738, %U A216139 676,709,685,761,703,3,703,728,707,660,675,667,633,649,660,3 %N A216139 a(n) = conjectured number of integers k such that n^k has no four consecutive identical digits. %Y A216139 Cf. A216063, A216064, A216065. %K A216139 nonn,base %O A216139 2,1 %A A216139 _V. Raman_, Sep 01 2012