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

Terms

a(0) =0a(1) =1a(2) =9a(3) =48a(4) =160a(5) =384a(6) =798a(7) =1468a(8) =2517a(9) =4041a(10) =6172a(11) =9063a(12) =12870a(13) =17746a(14) =23907a(15) =31581a(16) =40933a(17) =52227a(18) =65721a(19) =81676a(20) =100401a(21) =122136a(22) =147205a(23) =175944a(24) =208716a(25) =245833a(26) =287685a(27) =334665a(28) =387211a(29) =445701