T(2n+1, n+1), T given by A026758.

Terms

a(0) =1a(1) =3a(2) =11a(3) =43a(4) =174a(5) =721a(6) =3042a(7) =13022a(8) =56420a(9) =246977a(10) =1090846a(11) =4856162a(12) =21770665a(13) =98217318a(14) =445634370a(15) =2032434475a(16) =9313305870a(17) =42861416044a(18) =198038717055a(19) =918368326483