Number of (w,x,y,z) with all terms in {1,...,n} and w>2x and y>=3z.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =4a(5) =12a(6) =30a(7) =63a(8) =108a(9) =192a(10) =300a(11) =450a(12) =660a(13) =936a(14) =1260a(15) =1715a(16) =2240a(17) =2880a(18) =3672a(19) =4617a(20) =5670a(21) =7000a(22) =8470a(23) =10164a(24) =12144a(25) =14400a(26) =16848a(27) =19773a(28) =22932a(29) =26460