 Their complements,

There are also associated sequences, namely the Apéry numbers,

the Domb numbers (unsigned) or the number of 2"n"-step polygons on a diamond lattice,

and the Almkvist-Zudilin numbers,

where formula_58.The modular functions can be related as,

if the series converges and the sign chosen appropriately.It can also be observed that,

which implies,

and similarly using α3 and α'3.