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 A251737 #8 Feb 06 2017 17:53:00 %S A251737 1,1,3,5,17,66,181,508,1283,3664,10812,31171,88565,245524,692416, %T A251737 1968532,5609977,15928174,44982196,127190716,360208608,1021611491, %U A251737 2896270245,8202605953,23226285083,65780006703,186369631872,528047092459,1495905404102,4237308534243 %N A251737 Number of tilings of a 5 X n rectangle using n pentominoes of shapes L, U, I. %H A251737 Alois P. Heinz, <a href="/A251737/b251737.txt">Table of n, a(n) for n = 0..1000</a> %H A251737 Wikipedia, <a href="https://en.wikipedia.org/wiki/Pentomino">Pentomino</a> %e A251737 a(4) = 17: %e A251737 ._______. ._______. ._______. ._______. %e A251737 |_____. | | ._____| | | | | | | | ._| | %e A251737 | | ._|_| |_| ._. | | | | | | | | | | | %e A251737 | | |_. | | |_| |_| | | | | | | | | | | %e A251737 | |___| | |_____| | | | | | | | |_| | | %e A251737 |___|___| (4) |_______| (2) |_|_|_|_| (1) |_|___|_| (2) %e A251737 ._______. ._______. ._______. %e A251737 | ._| | | | ._| ._| | ._|_. | %e A251737 | | | | | | | | | | | | | | | %e A251737 | | | | | | | | | | | | | | | %e A251737 |_| | | | |_| |_| | |_| | |_| %e A251737 |___|_|_| (4) |___|___| (2) |___|___| (2) . %Y A251737 Cf. A174249, A233427, A247443, A247680, A249762, A251617. %K A251737 nonn %O A251737 0,3 %A A251737 _Alois P. Heinz_, Dec 07 2014