a(n) = T(4n,n), where T is the array defined in A025564.

A025572

a(n) = T(4n,n), where T is the array defined in A025564.

Terms

    a(0) =1a(1) =4a(2) =34a(3) =330a(4) =3381a(5) =35700a(6) =384307a(7) =4193020a(8) =46203670a(9) =513011312a(10) =5730482707a(11) =64324536822a(12) =724966763955

External references