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.

A319324 a(n) is the number of fixed polyglasses (polyiamonds which need only touch at corners) with n cells.

This page as a plain text file.
%I A319324 #22 Jun 06 2024 12:28:24
%S A319324 2,12,88,710,6054,53500,484784,4475010,41902626,396838992,3793117200,
%T A319324 36534684066
%N A319324 a(n) is the number of fixed polyglasses (polyiamonds which need only touch at corners) with n cells.
%C A319324 Polyglasses are to polyiamonds (A001420) as polyplets (A006770) are to polyominoes (A001168). The name derives from the 2-celled animal (diglass) which looks like an hourglass.
%H A319324 David Bevan, <a href="/A319324/a319324.png">The 88 fixed triglasses.</a>
%H A319324 Rebecca M. Bowen, Sadie Pruitt, and Douglas A. Torrance, <a href="https://arxiv.org/abs/2405.20793">Properties of regular Tangles</a>, arXiv:2405.20793 [math.CO], 2024. See p. 2.
%H A319324 Adam Gruber, <a href="https://devweb3000.cis.strath.ac.uk/~xpb16190/LatticeAnimals/LatticeAnimals.jar">Java program to count lattice animals</a>.
%e A319324 a(2) = 12: three rotations of a diamond, three rotations of an hourglass and six rotations of "two mountains".
%Y A319324 Cf. A001420 (fixed polyiamonds), A319325 (row convex polyglasses), A319326 (column convex polyglasses).
%K A319324 nonn,more,hard
%O A319324 1,1
%A A319324 _David Bevan_, Sep 18 2018
%E A319324 a(12) from _Aaron N. Siegel_, May 22 2022