8*n analog to Keith numbers.

Terms

a(0) =9a(1) =20a(2) =176a(3) =184a(4) =277a(5) =2669a(6) =15705a(7) =233202a(8) =241202a(9) =445657a(10) =742714a(11) =2095479a(12) =4697536a(13) =10508788a(14) =20308656a(15) =55683878a(16) =86603874