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 A220126 #11 Sep 05 2021 19:18:06 %S A220126 1,1,1,2,3,4,6,9,13,37,64,95,188,326,513,875,1449,2302,4289,7422, %T A220126 12072,21561,37559,62571,107806,184027,306628,532661,915705,1537768, %U A220126 2654311,4574383,7752577,13292546,22778306,38625110,66213867,113475693,192821642,330086669 %N A220126 Number of tilings of a 9 X n rectangle using integer-sided rectangular tiles of area 9. %H A220126 Alois P. Heinz, <a href="/A220126/b220126.txt">Table of n, a(n) for n = 0..1000</a> %e A220126 a(5) = 4, because there are 4 tilings of a 9 X 5 rectangle using integer-sided rectangular tiles of area 9: %e A220126 ._._._._._. ._____._._. ._._____._. ._._._____. %e A220126 | | | | | | | | | | | | | | | | | | %e A220126 | | | | | | | | | | | | | | | | | | %e A220126 | | | | | | |_____| | | | |_____| | | | |_____| %e A220126 | | | | | | | | | | | | | | | | | | %e A220126 | | | | | | | | | | | | | | | | | | %e A220126 | | | | | | |_____| | | | |_____| | | | |_____| %e A220126 | | | | | | | | | | | | | | | | | | %e A220126 | | | | | | | | | | | | | | | | | | %e A220126 |_|_|_|_|_| |_____|_|_| |_|_____|_| |_|_|_____| %Y A220126 Column k=9 of A220122. %K A220126 nonn %O A220126 0,4 %A A220126 _Alois P. Heinz_, Dec 06 2012