a(n) = binomial(n+5,6) + binomial(n+3,3) + binomial(n+2,3) + binomial(n-1,1).

Terms

a(0) =0a(1) =6a(2) =22a(3) =60a(4) =142a(5) =305a(6) =607a(7) =1134a(8) =2008a(9) =3396a(10) =5520a(11) =8668a(12) =13206a(13) =19591a(14) =28385a(15) =40270a(16) =56064a(17) =76738a(18) =103434a(19) =137484a(20) =180430a(21) =234045a(22) =300355a(23) =381662a(24) =480568a(25) =600000a(26) =743236a(27) =913932a(28) =1116150a(29) =1354387