Number of `(n,2)'-sequences of length 2n.

A007281

Number of `(n,2)'-sequences of length 2n.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =2a(4) =5a(5) =4a(6) =8a(7) =6a(8) =1a(9) =0a(10) =1a(11) =0a(12) =0

External references