Sum of rows of triangle defined in A001404.

Terms

a(0) =1a(1) =2a(2) =5a(3) =12a(4) =28a(5) =65a(6) =149a(7) =341a(8) =777a(9) =1769a(10) =4022a(11) =9140a(12) =20763a(13) =47156a(14) =107086a(15) =243162a(16) =552128a(17) =1253640a(18) =2846424a(19) =6462827a(20) =14673824a(21) =33316766a(22) =75645245a(23) =171751292a(24) =389958283a(25) =885393129a(26) =2010268490