Euler transform of A000332.

Terms

a(0) =1a(1) =6a(2) =21a(3) =71a(4) =216a(5) =672a(6) =1982a(7) =5817a(8) =16582a(9) =46633a(10) =128704a(11) =350665a(12) =941715a(13) =2499640a(14) =6557378a(15) =17024095a(16) =43756166a(17) =111433472a(18) =281303882a(19) =704320180a(20) =1749727370a(21) =4314842893a(22) =10565857064a(23) =25700414815a(24) =62115621317a(25) =149214574760a(26) =356354881511a(27) =846292135184