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 A236580 #16 Jun 10 2022 06:14:18 %S A236580 1,4,25,154,943,5773,35344,216388,1324801,8110882,49657576,304020556, %T A236580 1861317163,11395616227,69767835259,427142397547,2615110919020, %U A236580 16010597772667,98022320649478,600125959188877,3674175070596919,22494548423870416,137719270059617428 %N A236580 The number of tilings of a 6 X (4n) floor with 1 X 4 tetrominoes. %C A236580 Tilings are counted irrespective of internal symmetry: Tilings that match each other after rotations and/or reflections are counted with their multiplicity. %H A236580 Mudit Aggarwal and Samrith Ram, <a href="https://arxiv.org/abs/2206.04437">Generating functions for straight polyomino tilings of narrow rectangles</a>, arXiv:2206.04437 [math.CO], 2022. %H A236580 R. J. Mathar, <a href="http://arxiv.org/abs/1311.6135">Paving rectangular regions...</a>, arXiv:1311.6135, Table 35. %H A236580 R. J. Mathar, <a href="http://arxiv.org/abs/1406.7788">Tilings of Rectangular Regions by Rectangular Tiles: Counts Derived from Transfer Matrices</a>, arXiv:1406.7788 [math.CO], eq. (26). %H A236580 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (7,-6,4,-1). %F A236580 G.f.: (1-x)^3/(-7*x+1+6*x^2-4*x^3+x^4). %p A236580 g := (1-x)^3/(-7*x+1+6*x^2-4*x^3+x^4) ; %p A236580 taylor(%,x=0,30) ; %p A236580 gfun[seriestolist](%) ; %Y A236580 Cf. A003269 (4Xn floor), A236579 - A236582. %K A236580 easy,nonn %O A236580 0,2 %A A236580 _R. J. Mathar_, Jan 29 2014