Number of (w,x,y,z) with all terms in {0,...,n} and 2w=floor((x+y+z)/2).

Terms

a(0) =1a(1) =4a(2) =13a(3) =32a(4) =63a(5) =108a(6) =171a(7) =256a(8) =365a(9) =500a(10) =665a(11) =864a(12) =1099a(13) =1372a(14) =1687a(15) =2048a(16) =2457a(17) =2916a(18) =3429a(19) =4000a(20) =4631a(21) =5324a(22) =6083a(23) =6912a(24) =7813a(25) =8788a(26) =9841a(27) =10976a(28) =12195a(29) =13500