Number of placements of brackets in a monomial of degree n in an algebra with two commutative multiplications.

A226909

Number of placements of brackets in a monomial of degree n in an algebra with two commutative multiplications.

Terms

    a(0) =1a(1) =2a(2) =4a(3) =14a(4) =44a(5) =164a(6) =616a(7) =2450a(8) =9908a(9) =41116a(10) =173144a(11) =739884a(12) =3196344a(13) =13944200a(14) =61327312a(15) =271653254a(16) =1210772124a(17) =5426133764a(18) =24435934568a(19) =110524288836a(20) =501864708968

External references