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

Terms

a(0) =0a(1) =1a(2) =12a(3) =63a(4) =202a(5) =496a(6) =1034a(7) =1923a(8) =3289a(9) =5280a(10) =8062a(11) =11820a(12) =16761a(13) =23110a(14) =31111a(15) =41030a(16) =53151a(17) =67777a(18) =85233a(19) =105862a(20) =130026a(21) =158109a(22) =190513a(23) =227659a(24) =269990a(25) =317967a(26) =372070a(27) =432801a(28) =500680a(29) =576246