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 A349187 #13 Apr 30 2022 20:57:50 %S A349187 1,0,0,0,0,6,6,6,2,10,86,118,166,152,372,1394,2450,3866,4946,10160, %T A349187 26380,50770,86522,131632,251150,548436,1075036,1918294,3205242, %U A349187 5953962,11962044,23255472,42565706,74859582,138078796,266506794,511327170,947685504,1713749022 %N A349187 Number of tilings of a 5 X n rectangle using n pentominoes of shapes X, Y, Z. %H A349187 Alois P. Heinz, <a href="/A349187/b349187.txt">Table of n, a(n) for n = 0..3700</a> %H A349187 Wikipedia, <a href="https://en.wikipedia.org/wiki/Pentomino">Pentomino</a> %H A349187 <a href="/index/Rec#order_20">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,3,13,7,8,1,-10,-14,-20,-8,-7,-38,-33,-2,0,-5,-16,-11). %F A349187 G.f.: (x^20 +6*x^19 +5*x^18 +7*x^15 +14*x^14 +7*x^13 +4*x^10 +2*x^9 +x^8 -2*x^7 -x^6 -7*x^5 -3*x^4 +1) / (11*x^20 +16*x^19 +5*x^18 +2*x^16 +33*x^15 +38*x^14 +7*x^13 +8*x^12 +20*x^11 +14*x^10 +10*x^9 -x^8 -8*x^7 -7*x^6 -13*x^5 -3*x^4 +1). %e A349187 a(5) = 6: %e A349187 ._________. ._________. %e A349187 |_. ._._| | | |___. ._| %e A349187 | |_| |_. | | |_ |_| | %e A349187 | |_. ._| | | ._| |_. | %e A349187 | ._|_| |_| (2) |_| |___| | (4) %e A349187 |_|_______| |_______|_| . %e A349187 . %e A349187 a(8) = 2: %e A349187 ._______________. %e A349187 |_. | |___. ._| | %e A349187 | | |___. |_|_. | %e A349187 | |___| |_|_. | | %e A349187 | ._| |___. | |_| (2) %e A349187 |_|_______|_|___| . %e A349187 . %Y A349187 Cf. A174249, A343529. %K A349187 nonn,easy %O A349187 0,6 %A A349187 _Alois P. Heinz_, Nov 09 2021