Number of partitions of an n-gon into (n-4) parts.

Terms

a(0) =3a(1) =32a(2) =225a(3) =1320a(4) =7007a(5) =34944a(6) =167076a(7) =775200a(8) =3517470a(9) =15690048a(10) =69052555a(11) =300638520a(12) =1297398375a(13) =5557977600a(14) =23663585880a(15) =100222246080a(16) =422559514170