a(n) = Sum_{0<=j<=i<=n} A027170(i, j).

Terms

a(0) =1a(1) =7a(2) =27a(3) =79a(4) =199a(5) =459a(6) =1003a(7) =2119a(8) =4383a(9) =8947a(10) =18115a(11) =36495a(12) =73303a(13) =146971a(14) =294363a(15) =589207a(16) =1178959a(17) =2358531a(18) =4717747a(19) =9436255a(20) =18873351a(21) =37747627a(22) =75496267a(23) =150993639a(24) =301988479a(25) =603978259a(26) =1207957923a(27) =2415917359a(28) =4831836343a(29) =9663674427