Column 1 of triangle A136228; also equals column 3 of square array A136217.

A136229

Column 1 of triangle A136228; also equals column 3 of square array A136217.

Terms

    a(0) =1a(1) =4a(2) =24a(3) =198a(4) =2116a(5) =28052a(6) =446560a(7) =8325700a(8) =178284892a(9) =4317391240a(10) =116757568072

External references