Number of length 2n n-ary words that can be built by repeatedly inserting doublets into the initially empty word.

A294491

Number of length 2n n-ary words that can be built by repeatedly inserting doublets into the initially empty word.

Terms

    a(0) =1a(1) =1a(2) =6a(3) =87a(4) =2092a(5) =71445a(6) =3183156a(7) =175466347a(8) =11544312984a(9) =883404542025

External references