cp's OEIS Frontend

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.

A367557 The number of fixed kissing polyominoes with n cells.

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%I A367557 #17 Sep 25 2024 11:30:30
%S A367557 4,40,260,1428,7184,34238,157398,705518,3104394,13469766,57811669,
%T A367557 245990766
%N A367557 The number of fixed kissing polyominoes with n cells.
%C A367557 Translations are allowed, but not rotations or reflections.
%C A367557 A polyomino is 'kissing' if there exist two cells that touch only at a corner such that no cell exists touching both edgewise simultaneously.
%C A367557 First thirteen terms calculated by filtering the output of Redelmeier's Algorithm.
%H A367557 Alain Goupil, Marie-Eve Pellerin, and Jérôme de Wouters d'Oplinter, <a href="https://doi.org/10.1016/j.dam.2017.09.003">Partially Directed Snake Polyominoes</a>, Discrete Applied Mathematics, Volume 236, 2018.
%e A367557 The smallest kissing polyomino has area 7; its four rotations determine the first term in the sequence:
%e A367557     OOO
%e A367557     O O
%e A367557     OO
%Y A367557 Cf. A182644, A376496.
%K A367557 nonn,hard,more
%O A367557 7,1
%A A367557 _Johann Peters_, Nov 22 2023
%E A367557 a(14)-a(18) from _John Mason_, Sep 25 2024