Number of (w,x,y,z) with all terms in {1,...,n} and w < (geometric mean of x,y,z).

Terms

a(0) =0a(1) =0a(2) =7a(3) =36a(4) =111a(5) =274a(6) =567a(7) =1056a(8) =1789a(9) =2859a(10) =4350a(11) =6370a(12) =9000a(13) =12387a(14) =16642a(15) =21906a(16) =28326a(17) =36064a(18) =45273a(19) =56151a(20) =68884a(21) =83685a(22) =100758a(23) =120316a(24) =142530a(25) =167745a(26) =196141a(27) =227976a(28) =263553a(29) =303172