Erroneous version of A027610.

Terms

a(0) =1a(1) =1a(2) =1a(3) =3a(4) =7a(5) =24a(6) =93a(7) =434a(8) =2110a(9) =10957a(10) =58713a(11) =321576a(12) =1792133a(13) =10131027a(14) =57949430a(15) =334970205a(16) =1953890318a(17) =11489753730a(18) =68054102361a(19) =405715557048