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 A286347 #13 Nov 19 2018 11:01:58 %S A286347 1,1,15,188,3763,54368,790504,11771179,176285795,2627027061, %T A286347 39172906410,584774465361,8725442013820,130117410190768, %U A286347 1940656499251689,28950613608637003,431889355175650435,6442566792491842258,96102610815876310611,1433558139553752297236 %N A286347 Number of tilings of a 6 X n rectangle using pentominoes of shapes X, Y, T and monominoes. %H A286347 Alois P. Heinz, <a href="/A286347/b286347.txt">Table of n, a(n) for n = 0..852</a> %H A286347 Wikipedia, <a href="https://en.wikipedia.org/wiki/Pentomino">Pentomino</a> %Y A286347 Cf. A247125, A278330, A278456, A278657, A278877, A278964, A286391, A321589. %K A286347 nonn %O A286347 0,3 %A A286347 _Alois P. Heinz_, May 08 2017