Number of (w,x,y,z) with all terms in {0,...,n} and |w-x|<|x-y|<|y-z|.

Terms

a(0) =0a(1) =0a(2) =2a(3) =14a(4) =44a(5) =110a(6) =228a(7) =426a(8) =726a(9) =1168a(10) =1780a(11) =2612a(12) =3700a(13) =5104a(14) =6866a(15) =9058a(16) =11728a(17) =14958a(18) =18804a(19) =23358a(20) =28682a(21) =34880a(22) =42020a(23) =50216a(24) =59544a(25) =70128a(26) =82050a(27) =95446a(28) =110404a(29) =127070