Fourth diagonal (m=3) of triangle A084938; a(n) = A084938(n+3,n) = (n^3 + 9*n^2 + 26*n)/6.

Terms

a(0) =0a(1) =6a(2) =16a(3) =31a(4) =52a(5) =80a(6) =116a(7) =161a(8) =216a(9) =282a(10) =360a(11) =451a(12) =556a(13) =676a(14) =812a(15) =965a(16) =1136a(17) =1326a(18) =1536a(19) =1767a(20) =2020a(21) =2296a(22) =2596a(23) =2921a(24) =3272a(25) =3650a(26) =4056a(27) =4491a(28) =4956a(29) =5452