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

Terms

a(0) =1a(1) =7a(2) =25a(3) =59a(4) =117a(5) =202a(6) =323a(7) =482a(8) =689a(9) =945a(10) =1261a(11) =1637a(12) =2085a(13) =2604a(14) =3207a(15) =3892a(16) =4673a(17) =5547a(18) =6529a(19) =7615a(20) =8821a(21) =10142a(22) =11595a(23) =13174a(24) =14897a(25) =16757a(26) =18773a(27) =20937a(28) =23269a(29) =25760