Number of free polyforms made of T-pipes connected end-to-end (not perpendicular).

A390515

Number of free polyforms made of T-pipes connected end-to-end (not perpendicular).

Terms

    a(0) =1a(1) =4a(2) =15a(3) =99a(4) =630a(5) =4599a(6) =34099a(7) =261603a(8) =2036026a(9) =16075980a(10) =128214840a(11) =1031495768

External references