Number of triples (w,x,y) with all terms in {0,...,n} and w <= floor((x+y)/3).

Terms

a(0) =1a(1) =4a(2) =12a(3) =27a(4) =50a(5) =84a(6) =131a(7) =192a(8) =270a(9) =367a(10) =484a(11) =624a(12) =789a(13) =980a(14) =1200a(15) =1451a(16) =1734a(17) =2052a(18) =2407a(19) =2800a(20) =3234a(21) =3711a(22) =4232a(23) =4800a(24) =5417a(25) =6084a(26) =6804a(27) =7579a(28) =8410a(29) =9300