Squares of the central trinomial coefficients (A002426).

A168597

Squares of the central trinomial coefficients (A002426).

Terms

    a(0) =1a(1) =1a(2) =9a(3) =49a(4) =361a(5) =2601a(6) =19881a(7) =154449a(8) =1225449a(9) =9853321a(10) =80156209a(11) =658076409a(12) =5444816521a(13) =45343869481a(14) =379735715529

External references