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 A173784 #2 Mar 30 2012 17:22:55 %S A173784 1,2,4,6,9,12,18,23,28,34,42,49,61,68,80,91,103,111,128,138,156 %N A173784 Number of numbers k such that 1/k is in the Cantor set and 3^n <= k < 3^(n+1). %C A173784 This sequence gives the length of the rows in the irregular triangle A170952. See A121153 for the values of k. %K A173784 nonn %O A173784 0,2 %A A173784 _T. D. Noe_, Feb 24 2010