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

Terms

a(0) =0a(1) =1a(2) =8a(3) =33a(4) =88a(5) =185a(6) =336a(7) =553a(8) =848a(9) =1233a(10) =1720a(11) =2321a(12) =3048a(13) =3913a(14) =4928a(15) =6105a(16) =7456a(17) =8993a(18) =10728a(19) =12673a(20) =14840a(21) =17241a(22) =19888a(23) =22793a(24) =25968a(25) =29425a(26) =33176a(27) =37233a(28) =41608a(29) =46313