T(n,1) + T(n,2) + ... + T(n,n), T given by A026703.

Terms

a(0) =1a(1) =2a(2) =5a(3) =12a(4) =27a(5) =64a(6) =141a(7) =330a(8) =721a(9) =1674a(10) =3641a(11) =8410a(12) =18241a(13) =41986a(14) =90897a(15) =208708a(16) =451255a(17) =1034292a(18) =2234205a(19) =5114220a(20) =11039871a(21) =25246376a(22) =54470817a(23) =124474648a(24) =268460375a(25) =613133340a(26) =1321990349a(27) =3017984992a(28) =6505697947