Number of (w,x,y,z) with all terms in {1,...,n} and w*x=3*y*z.

Terms

a(0) =0a(1) =0a(2) =0a(3) =8a(4) =14a(5) =18a(6) =48a(7) =56a(8) =74a(9) =126a(10) =154a(11) =166a(12) =262a(13) =278a(14) =318a(15) =422a(16) =480a(17) =500a(18) =674a(19) =698a(20) =800a(21) =956a(22) =1024a(23) =1052a(24) =1308a(25) =1378a(26) =1458a(27) =1698a(28) =1852a(29) =1888