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

Terms

a(0) =0a(1) =0a(2) =1a(3) =19a(4) =80a(5) =230a(6) =521a(7) =1019a(8) =1800a(9) =2966a(10) =4593a(11) =6819a(12) =9768a(13) =13566a(14) =18353a(15) =24339a(16) =31640a(17) =40478a(18) =51025a(19) =63523a(20) =78168a(21) =95230a(22) =114881a(23) =137459a(24) =163184a(25) =192374a(26) =225265a(27) =262251a(28) =303568a(29) =349606