Backwards shallow diagonal sums of Catalan triangle A009766.

Terms

a(0) =1a(1) =1a(2) =3a(3) =7a(4) =20a(5) =59a(6) =184a(7) =593a(8) =1964a(9) =6642a(10) =22845a(11) =79667a(12) =281037a(13) =1001092a(14) =3595865a(15) =13009673a(16) =47366251a(17) =173415176a(18) =638044203a(19) =2357941142a(20) =8748646386a(21) =32576869203a(22) =121701491701a(23) =456012458965