T(n,n-1), array T given by A047010.

Terms

a(0) =1a(1) =1a(2) =3a(3) =12a(4) =46a(5) =172a(6) =651a(7) =2478a(8) =9457a(9) =36228a(10) =139249a(11) =536687a(12) =2073540a(13) =8028826a(14) =31147792a(15) =121045410a(16) =471128566a(17) =1836259944a(18) =7165975248a(19) =27997121205a(20) =109497724812a(21) =428659516902