a(n) = binomial(n+5, 5)*7^n.

Terms

a(0) =1a(1) =42a(2) =1029a(3) =19208a(4) =302526a(5) =4235364a(6) =54353838a(7) =652246056a(8) =7419298887a(9) =80787921214a(10) =848273172747