QECC [[20,8,4]]

This pure code is based on a weakly self-dual binary code with generator matrix: 
[1 0 0 0 0 0 1 0 0 1 0 0 1 1 1 0 0 1 0 1]
[0 1 0 0 0 0 0 0 1 1 1 0 1 1 1 1 1 0 1 0]
[0 0 1 0 0 0 1 1 0 1 0 0 0 1 0 1 1 1 0 0]
[0 0 0 1 0 0 1 1 0 1 1 1 1 1 0 0 1 1 1 1]
[0 0 0 0 1 0 0 1 1 0 0 1 1 1 1 1 0 1 1 0]
[0 0 0 0 0 1 0 0 1 1 1 1 1 0 0 0 0 1 0 1]

Binary matrix with stabilizers/seed generators and circuit for encoding:

Copyright © Markus Grassl (grassl@ira.uka.de) 22.08.2000