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.
Table of n, a(n) for n=1..11.
David Bevan, The 88 fixed triglasses.
Adam Gruber, Java program to count lattice animals.
a(2) = 12: three rotations of a diamond, three rotations of an hourglass and six rotations of "two mountains".
Cf. A001420 (fixed polyiamonds), A319325 (row convex polyglasses), A319326 (column convex polyglasses).
Sequence in context: A181345 A193125 A305868 * A059435 A192621 A143923
Adjacent sequences: A319321 A319322 A319323 * A319325 A319326 A319327
David Bevan, Sep 18 2018