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

Terms

a(0) =0a(1) =1a(2) =2a(3) =9a(4) =22a(5) =41a(6) =72a(7) =115a(8) =170a(9) =243a(10) =334a(11) =443a(12) =576a(13) =733a(14) =914a(15) =1125a(16) =1366a(17) =1637a(18) =1944a(19) =2287a(20) =2666a(21) =3087a(22) =3550a(23) =4055a(24) =4608a(25) =5209a(26) =5858a(27) =6561a(28) =7318a(29) =8129