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 A130180 #8 Mar 31 2012 10:28:28 %S A130180 5,3,12,2,6,8,4,1,13,8,7,14,8,3,9,1,5,12,4,0,13,4,7,7,1,4,7,2,5,8,2,4, %T A130180 8,7,1,10,5,2,8,4,2,10,2,6,10,2,3,6,2,4,4,2,3,9,2,3,8,1,3,8,5,3,6,4,6, %U A130180 8,4,3,10,0,1,6,3,6,6,4,2,7,2,1 %N A130180 Number of numbers k > 1 such that (sum of digits of k^n)*(sum of digits of k^(n+1)) = k. %H A130180 Lars Blomberg, <a href="/A130180/b130180.txt">Table of n, a(n) for n = 1..116</a> %e A130180 80, 1036, 1215 are the only numbers k > 1 such that (sum of digits of k^2)*(sum of digits of k^3) = k, hence a(2) = 3. %Y A130180 Cf. A126783 (smallest k), A130179 (upper bound), A130181 (largest k). %K A130180 nonn,base,hard %O A130180 1,1 %A A130180 _Klaus Brockhaus_, May 14 2007 %E A130180 a(55)-a(80) and b-file from _Lars Blomberg_, Dec 11 2011