Number of (w,x,y) with all terms in {0,...,n} and w<=x+y and x<=y.

Terms

a(0) =1a(1) =5a(2) =15a(3) =33a(4) =62a(5) =104a(6) =162a(7) =238a(8) =335a(9) =455a(10) =601a(11) =775a(12) =980a(13) =1218a(14) =1492a(15) =1804a(16) =2157a(17) =2553a(18) =2995a(19) =3485a(20) =4026a(21) =4620a(22) =5270a(23) =5978a(24) =6747a(25) =7579a(26) =8477a(27) =9443a(28) =10480a(29) =11590