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 A387004 #5 Aug 15 2025 15:58:57 %S A387004 1,1,1,2,7,3,5,49,41,8 %N A387004 Triangle read by rows: T(n,d) is the number of free, properly d-dimensional (d,2)-polyominoids of size n, 2 <= d <= n+1. %H A387004 Wikipedia, <a href="https://en.wikipedia.org/wiki/Polyominoid">Polyominoid</a>. %H A387004 <a href="/index/Pol#polyominoes">Index entries for sequences related to polyominoes</a>. %F A387004 T(n,d) = A387003(n,d) - A387003(n,d-1) (with A387003(n,1) = 0). %e A387004 Triangle begins: %e A387004 n\d| 2 3 4 5 %e A387004 ---+----------- %e A387004 1 | 1 %e A387004 2 | 1 1 %e A387004 3 | 2 7 3 %e A387004 4 | 5 49 41 8 %Y A387004 Cf. A000105 (column d=2), A049430 (polyominoes), A365566 (polysticks), A387002 (fixed), A387003, A387005 (row sums). %K A387004 nonn,tabl,more %O A387004 1,4 %A A387004 _Pontus von Brömssen_, Aug 14 2025