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 A056843 #11 Jul 02 2025 16:02:00 %S A056843 0,3,1,9,15,59,152,513,1539,4993,15836 %N A056843 Number of polydudes(1): a(n) is the number of polydudes with n cells. See the first link for the source of this sequence. The definition is unknown. Not the same as A091130. %C A056843 The polydudes(1) (this sequence) and the polydudes(2) (A091130) are both subsets of the polydrafters (A056842). %C A056843 Speculation about the definition: There are 3 2-drafters that have no 30-degree angles. It appears that all polydudes are unions of these 3 2-drafters. All the pictured 5-dudes and 6-dudes have this property and the numbers of n-drafters with this property agree with the first 5 terms. I believe there is only one 6-drafter with this property that is not in the picture. This one was probably excluded because it has a 30-degree external angle, which none of the other polydudes can fit into. I can't guess what other exclusions might occur for n > 6. (D.R.W.) %H A056843 M. Vicher, <a href="http://www.vicher.cz/puzzle/polyforms.htm">Polyforms</a> %H A056843 M. Vicher, <a href="http://www.vicher.cz/puzzle/polyform/dude/pentdude.htm">Polydudes</a> %e A056843 The second link shows all 5-dudes and 6-dudes. %Y A056843 Cf. A056842, A091130. %K A056843 nonn,obsc %O A056843 1,2 %A A056843 _James Sellers_, Aug 28 2000 %E A056843 Edited by _David Wasserman_, Dec 19 2003