a(n) = Sum_{i=1..n} T(i,n-i), where T is A049615.

Terms

a(0) =0a(1) =0a(2) =2a(3) =6a(4) =13a(5) =22a(6) =36a(7) =52a(8) =73a(9) =98a(10) =130a(11) =164a(12) =207a(13) =252a(14) =306a(15) =368a(16) =439a(17) =512a(18) =598a(19) =686a(20) =787a(21) =898a(22) =1022a(23) =1148a(24) =1291a(25) =1440a(26) =1604a(27) =1778a(28) =1969a(29) =2162