Truncated triangular pyramid numbers: a(n) = Sum_{k=9..n} (k*(k+1)/2 - 45).

Terms

a(0) =0a(1) =10a(2) =31a(3) =64a(4) =110a(5) =170a(6) =245a(7) =336a(8) =444a(9) =570a(10) =715a(11) =880a(12) =1066a(13) =1274a(14) =1505a(15) =1760a(16) =2040a(17) =2346a(18) =2679a(19) =3040a(20) =3430a(21) =3850a(22) =4301a(23) =4784a(24) =5300a(25) =5850a(26) =6435a(27) =7056a(28) =7714a(29) =8410