T(n,n-4), where T is the array in A055830.

Terms

a(0) =5a(1) =15a(2) =31a(3) =54a(4) =85a(5) =125a(6) =175a(7) =236a(8) =309a(9) =395a(10) =495a(11) =610a(12) =741a(13) =889a(14) =1055a(15) =1240a(16) =1445a(17) =1671a(18) =1919a(19) =2190a(20) =2485a(21) =2805a(22) =3151a(23) =3524a(24) =3925a(25) =4355a(26) =4815a(27) =5306a(28) =5829a(29) =6385