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) =1a(2) =9a(3) =39a(4) =121a(5) =285a(6) =579a(7) =1069a(8) =1815a(9) =2904a(10) =4396a(11) =6417a(12) =9060a(13) =12448a(14) =16704a(15) =21969a(16) =28414a(17) =36153a(18) =45393a(19) =56272a(20) =69012a(21) =83814a(22) =100888a(23) =120447a(24) =142692a(25) =167944a(26) =196341a(27) =228231a(28) =263815a(29) =303435