Partial sums of round(7^n/10).

Terms

a(0) =0a(1) =1a(2) =6a(3) =40a(4) =280a(5) =1961a(6) =13726a(7) =96080a(8) =672560a(9) =4707921a(10) =32955446a(11) =230688120a(12) =1614816840a(13) =11303717881a(14) =79126025166a(15) =553882176160