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) =9a(4) =30a(5) =92a(6) =198a(7) =396a(8) =684a(9) =1152a(10) =1760a(11) =2650a(12) =3780a(13) =5292a(14) =7140a(15) =9555a(16) =12376a(17) =15936a(18) =20088a(19) =25110a(20) =30870a(21) =37800a(22) =45540a(23) =54692a(24) =64944a(25) =76752a(26) =89856a(27) =104949a(28) =121394a(29) =140140