T(n,0) + T(n,1) + ... + T(n,n), T given by A026670.

Terms

a(0) =1a(1) =2a(2) =5a(3) =10a(4) =23a(5) =46a(6) =103a(7) =206a(8) =455a(9) =910a(10) =1993a(11) =3986a(12) =8679a(13) =17358a(14) =37633a(15) =75266a(16) =162643a(17) =325286a(18) =701075a(19) =1402150a(20) =3015563a(21) =6031126a(22) =12948083a(23) =25896166a(24) =55513327a(25) =111026654a(26) =237705547a(27) =475411094a(28) =1016736115a(29) =2033472230