T(n,0) + T(n,1) + ... + T(n,n), T given by A026659.

Terms

a(0) =1a(1) =2a(2) =4a(3) =10a(4) =20a(5) =42a(6) =84a(7) =196a(8) =392a(9) =842a(10) =1684a(11) =3878a(12) =7756a(13) =16786a(14) =33572a(15) =76846a(16) =153692a(17) =333998a(18) =667996a(19) =1523448a(20) =3046896a(21) =6639150a(22) =13278300a(23) =30206468a(24) =60412936a(25) =131892226a(26) =263784452a(27) =598952096a(28) =1197904192a(29) =2619074230