Column 4 of A052250.

Terms

a(0) =1a(1) =4a(2) =10a(3) =24a(4) =55a(5) =132a(6) =322a(7) =804a(8) =2051a(9) =5304a(10) =13886a(11) =36716a(12) =97882a(13) =262756a(14) =709658a(15) =1926748a(16) =5255707a(17) =14396048a(18) =39580338a(19) =109190052a(20) =302148814a(21) =838449236a(22) =2332652648a(23) =6505071080a(24) =18180441512a(25) =50914047384a(26) =142853059922a(27) =401517522844