Association types in 2-dimensional algebra.

Terms

a(0) =1a(1) =2a(2) =8a(3) =39a(4) =212a(5) =1232a(6) =7492a(7) =47082a(8) =303336a(9) =1992826a(10) =13299624a(11) =89912992a(12) =614474252a(13) =4238138216a(14) =29463047072a(15) =206234876287