T(n,n+3), array T as in A047030.

Terms

a(0) =1a(1) =4a(2) =15a(3) =56a(4) =209a(5) =784a(6) =2958a(7) =11220a(8) =42753a(9) =163548a(10) =627770a(11) =2416804a(12) =9328384a(13) =36087780a(14) =139890764a(15) =543246696a(16) =2113015731a(17) =8230687548a(18) =32102370550a(19) =125358442460a(20) =490049744789