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 A115687 #5 Mar 30 2012 17:40:35 %S A115687 4,9,49,64,121,169,289,400,512,625,900,961,968,1156,1225,1568,1849, %T A115687 2048,2401,2888,3125,3136,3364,3481,3721,4000,4900,4913,5041,5329, %U A115687 5408,6400,6859,6889,7396,8192,8575,9000,9604,10201,10648,10816,10952 %N A115687 Powerful(1) numbers (A001694) whose digit reversal is a semiprime (A001358). %H A115687 <a href="/index/Pow#powerful">Index entries for sequences related to powerful numbers</a> %e A115687 968=2^3*11^2 is powerful and 869=11*79 is semiprime. %Y A115687 Cf. A001358, A001694, A115688. %K A115687 nonn,base %O A115687 1,1 %A A115687 _Giovanni Resta_, Jan 31 2006