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 A247775 #8 May 02 2022 10:03:06 %S A247775 1,1,5,55,493,3930,27207,207118,1622723,12544364,95912510,732066083, %T A247775 5616480627,43128778000,330817187318,2536012919124,19443866141395, %U A247775 149118307026576,1143608532988558,8769818352137034,67250342436670138,515711365536657077,3954797365004436075 %N A247775 Number of tilings of a 5 X n rectangle using n pentominoes of any but the X shape. %H A247775 Alois P. Heinz, <a href="/A247775/b247775.txt">Table of n, a(n) for n = 0..500</a> %H A247775 Wikipedia, <a href="https://en.wikipedia.org/wiki/Pentomino">Pentomino</a> %Y A247775 Column k=0 of A247711. %Y A247775 Cf. A174249, A233427. %K A247775 nonn %O A247775 0,3 %A A247775 _Alois P. Heinz_, Sep 23 2014