a(n) = binomial(3*n+2,3).

Terms

a(0) =10a(1) =56a(2) =165a(3) =364a(4) =680a(5) =1140a(6) =1771a(7) =2600a(8) =3654a(9) =4960a(10) =6545a(11) =8436a(12) =10660a(13) =13244a(14) =16215a(15) =19600a(16) =23426a(17) =27720a(18) =32509a(19) =37820a(20) =43680a(21) =50116a(22) =57155a(23) =64824a(24) =73150a(25) =82160a(26) =91881a(27) =102340a(28) =113564a(29) =125580