T(n,0) + T(n,1) + ... + T(n,n), T given by A027907.

Terms

a(0) =1a(1) =2a(2) =6a(3) =17a(4) =50a(5) =147a(6) =435a(7) =1290a(8) =3834a(9) =11411a(10) =34001a(11) =101400a(12) =302615a(13) =903632a(14) =2699598a(15) =8068257a(16) =24121674a(17) =72137547a(18) =215786649a(19) =645629160a(20) =1932081885a(21) =5782851966a(22) =17311097568a(23) =51828203475a(24) =155188936431a(25) =464732722872