a(n) = 7 + floor(Sum_{j=1..n-1} a(j) / 2).

Terms

a(0) =7a(1) =10a(2) =15a(3) =23a(4) =34a(5) =51a(6) =77a(7) =115a(8) =173a(9) =259a(10) =389a(11) =583a(12) =875a(13) =1312a(14) =1968a(15) =2952a(16) =4428a(17) =6642a(18) =9963a(19) =14945a(20) =22417a(21) =33626a(22) =50439a(23) =75658a(24) =113487a(25) =170231a(26) =255346a(27) =383019a(28) =574529a(29) =861793