9-gonal (or enneagonal) pyramidal numbers: a(n) = n*(n+1)*(7*n-4)/6.

Terms

a(0) =0a(1) =1a(2) =10a(3) =34a(4) =80a(5) =155a(6) =266a(7) =420a(8) =624a(9) =885a(10) =1210a(11) =1606a(12) =2080a(13) =2639a(14) =3290a(15) =4040a(16) =4896a(17) =5865a(18) =6954a(19) =8170a(20) =9520a(21) =11011a(22) =12650a(23) =14444a(24) =16400a(25) =18525a(26) =20826a(27) =23310a(28) =25984a(29) =28855