Sum along upward diagonal of Pascal triangle to halfway point.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =4a(5) =5a(6) =6a(7) =7a(8) =23a(9) =30a(10) =38a(11) =47a(12) =141a(13) =188a(14) =245a(15) =313a(16) =888a(17) =1201a(18) =1594a(19) =2080a(20) =5676a(21) =7756a(22) =10429a(23) =13817a(24) =36622a(25) =50439a(26) =68497a(27) =91804a(28) =237821a(29) =329625