a(n) = 5*7^n+1.

Terms

a(0) =6a(1) =36a(2) =246a(3) =1716a(4) =12006a(5) =84036a(6) =588246a(7) =4117716a(8) =28824006a(9) =201768036a(10) =1412376246a(11) =9886633716a(12) =69206436006a(13) =484445052036