a(n) = 10 * binomial(3*n+10,n)/(3*n+10).

Terms

a(0) =1a(1) =10a(2) =75a(3) =510a(4) =3325a(5) =21252a(6) =134550a(7) =848250a(8) =5340060a(9) =33622600a(10) =211915132a(11) =1337675430a(12) =8458829925a(13) =53591180360a(14) =340185835500