Partial sums of round(5^n/8).

Terms

a(0) =0a(1) =1a(2) =4a(3) =20a(4) =98a(5) =489a(6) =2442a(7) =12208a(8) =61036a(9) =305177a(10) =1525880a(11) =7629396a(12) =38146974a(13) =190734865a(14) =953674318a(15) =4768371584a(16) =23841857912a(17) =119209289553a(18) =596046447756