a(n) = Sum_{i=1..n} C(i+5,6)^3.

Terms

a(0) =1a(1) =344a(2) =22296a(3) =615000a(4) =9876000a(5) =108487128a(6) =897376152a(7) =5950405848a(8) =33031486875a(9) =158406862000a(10) =671944398512