Expressible as C(m,3) + C(n,3) in at least 3 ways.

Terms

a(0) =102424a(1) =2421440a(2) =10057740a(3) =14388660a(4) =15862700a(5) =18491560a(6) =19971260a(7) =38769500a(8) =44795730a(9) =49915281a(10) =60110904a(11) =76405140a(12) =93730924a(13) =99144220a(14) =141575456a(15) =142908016a(16) =168201860a(17) =169065400a(18) =200262964a(19) =307690800a(20) =318547020a(21) =412814445