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 A247738 #6 Feb 07 2017 10:27:39
%S A247738 0,0,0,8,88,1024,10388,99840,935900,8415368,74295280,645535244,
%T A247738 5545784444,47152918764,397457338488,3327197881716,27688757985292,
%U A247738 229256300558340,1889667799688076,15514699106805468,126939424800685264,1035396864840877088,8421920979218715332
%N A247738 Total number of N shapes in all tilings of a 5 X n rectangle with pentominoes of any shape.
%H A247738 Alois P. Heinz, <a href="/A247738/b247738.txt">Table of n, a(n) for n = 0..500</a>
%H A247738 Wikipedia, <a href="https://en.wikipedia.org/wiki/Pentomino">Pentomino</a>
%F A247738 a(n) = Sum_{k>0} k * A247705(n,k).
%Y A247738 Cf. A174249, A233427, A247705.
%K A247738 nonn
%O A247738 0,4
%A A247738 _Alois P. Heinz_, Sep 23 2014