a(n) = T(n,0) + T(n,1) + ... + T(n,n), T given by A026907.

Terms

a(0) =1a(1) =26a(2) =100a(3) =272a(4) =640a(5) =1400a(6) =2944a(7) =6056a(8) =12304a(9) =24824a(10) =49888a(11) =100040a(12) =200368a(13) =401048a(14) =802432a(15) =1605224a(16) =3210832a(17) =6422072a(18) =12844576a(19) =25689608a(20) =51379696a(21) =102759896a(22) =205520320a(23) =411041192a(24) =822082960a(25) =1644166520a(26) =3288333664a(27) =6576667976a(28) =13153336624a(29) =26306673944