a(n) = 5*7^n.

Terms

a(0) =5a(1) =35a(2) =245a(3) =1715a(4) =12005a(5) =84035a(6) =588245a(7) =4117715a(8) =28824005a(9) =201768035a(10) =1412376245a(11) =9886633715a(12) =69206436005a(13) =484445052035