a(n) = binomial(n,2)*(binomial(n-1,2) + 2).

Terms

a(0) =0a(1) =2a(2) =9a(3) =30a(4) =80a(5) =180a(6) =357a(7) =644a(8) =1080a(9) =1710a(10) =2585a(11) =3762a(12) =5304a(13) =7280a(14) =9765a(15) =12840a(16) =16592a(17) =21114a(18) =26505a(19) =32870a(20) =40320a(21) =48972a(22) =58949a(23) =70380a(24) =83400a(25) =98150a(26) =114777a(27) =133434a(28) =154280a(29) =177480