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 A334617 #31 Oct 04 2020 02:44:56 %S A334617 1,2,8,57,806,20840,1038266,97115638,17213517207,5768580741287 %N A334617 a(n) is the number of ways to tile a size n staircase polyomino with staircase polyominoes. %C A334617 A size-n staircase polynomo is a polyomino consisting of n left-aligned rows in increasing length of 1, 2, ..., n. Rotations of staircase polyominoes are also polyominoes. %H A334617 Code Golf Stack Exchange user "Bubbler", <a href="https://codegolf.stackexchange.com/q/210748/53884">Tiling a staircase with staircases</a>. %e A334617 For n = 3 the a(3) = 8 tilings are: %e A334617 +---+ +---+ +---+ +---+ %e A334617 | | | | | | | | %e A334617 +---+---+ + +---+ +---+---+ +---+---+ %e A334617 | | | | | | | | | | | %e A334617 +---+---+---+, +---+---+---+, + +---+---+, +---+ +---+, %e A334617 | | | | | | | | | | | | | | %e A334617 +---+---+---+ +---+---+---+ +---+---+---+ +---+---+---+ %e A334617 +---+ +---+ +---+ +---+ %e A334617 | | | | | | | | %e A334617 +---+---+ +---+---+ +---+---+ + +---+ %e A334617 | | | | | | | | | %e A334617 +---+ +---+, + +---+---+, +---+ +---+, + +---+. %e A334617 | | | | | | | | | | | | | %e A334617 +---+---+---+ +---+---+---+ +---+---+---+ +---+---+---+ %Y A334617 Cf. A000105, A045846, A219924, A254414, A335547. %K A334617 nonn,more %O A334617 1,2 %A A334617 _Peter Kagey_, Sep 08 2020 %E A334617 a(8) from _Seiichi Manyama_, Sep 09 2020 %E A334617 a(9)-a(10) from _Bert Dobbelaere_, Sep 12 2020