Binomial coefficients C(2n,n-3).

Terms

a(0) =1a(1) =8a(2) =45a(3) =220a(4) =1001a(5) =4368a(6) =18564a(7) =77520a(8) =319770a(9) =1307504a(10) =5311735a(11) =21474180a(12) =86493225a(13) =347373600a(14) =1391975640a(15) =5567902560a(16) =22239974430a(17) =88732378800a(18) =353697121050