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 A164342 #10 Jul 08 2012 14:41:06 %S A164342 1,4,9,27,61,185,469,1456,4368,14720,50800,190149,735451,3001161, %T A164342 12659652,55462967,250186665,1163114375,5548002866,27151477487, %U A164342 135968479892,696511087808,3643182769117,19449907766921,105843172596610 %N A164342 Row sums of table A164341. %H A164342 T. Kyle Petersen and Bridget Eileen Tenner, <a href="http://arxiv.org/abs/1202.5319">How to write a permutation as a product of involutions (and why you might care)</a>, arXiv:1202.5319, 2012 %Y A164342 Cf. A164341. %K A164342 nonn %O A164342 1,2 %A A164342 _Wouter Meeussen_, Aug 13 2009