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 A354132 #9 May 18 2022 13:13:08 %S A354132 1,3,48,405,4185,40320,397755,3892293,38193444,374425263,3671810235, %T A354132 36003770640,353046480345,3461866214283,33946152068808, %U A354132 332866572321933,3263999126947497,32005882711563552,313840950402409011,3077438640586986141,30176522977460549436 %N A354132 Number of tilings of a 3 X n rectangle using 2 X 2 and 1 X 1 tiles, right trominoes and dominoes. %C A354132 Tiling algorithm see A351322. %H A354132 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (6,38,0,-68,24,-3). %F A354132 G.f.: (1 - 3*x - 8*x^2 + 3*x^3 - x^4) / (1 - 6*x - 38*x^2 + 68*x^4 - 24*x^5 + 3*x^6). %F A354132 a(n) = 6*a(n-1) + 38*a(n-2) - 68*a(n-4) + 24*a(n-5) - 3*a(n-6). %e A354132 a(2) = 48, see 2 X 3, A354131. %o A354132 (Maxima), see A352589. %Y A354132 Cf. A351322, A352589, A354130, A354131. %K A354132 nonn,easy %O A354132 0,2 %A A354132 _Gerhard Kirchner_, May 18 2022