a(n) = T(n,n-6), array T as in A055818.

Terms

a(0) =1a(1) =95a(2) =336a(3) =848a(4) =1800a(5) =3422a(6) =6017a(7) =9974a(8) =15782a(9) =24045a(10) =35498a(11) =51024a(12) =71672a(13) =98676a(14) =133475a(15) =177734a(16) =233366a(17) =302555a(18) =387780a(19) =491840a(20) =617880a(21) =769418a(22) =950373a(23) =1165094a(24) =1418390a(25) =1715561a(26) =2062430a(27) =2465376a(28) =2931368a(29) =3468000