a(n) = C(n+3,4) + 3*C(n+1,3) + 5*C(n-1,2) + 7*n - 15 for n >= 3; a(1)=1, a(2)=10.

Terms

a(0) =1a(1) =10a(2) =38a(3) =93a(4) =180a(5) =308a(6) =487a(7) =728a(8) =1043a(9) =1445a(10) =1948a(11) =2567a(12) =3318a(13) =4218a(14) =5285a(15) =6538a(16) =7997a(17) =9683a(18) =11618a(19) =13825a(20) =16328a(21) =19152a(22) =22323a(23) =25868a(24) =29815a(25) =34193a(26) =39032a(27) =44363a(28) =50218a(29) =56630