38-gonal numbers: a(n) = n*(18*n-17).

Terms

a(0) =0a(1) =1a(2) =38a(3) =111a(4) =220a(5) =365a(6) =546a(7) =763a(8) =1016a(9) =1305a(10) =1630a(11) =1991a(12) =2388a(13) =2821a(14) =3290a(15) =3795a(16) =4336a(17) =4913a(18) =5526a(19) =6175a(20) =6860a(21) =7581a(22) =8338a(23) =9131a(24) =9960a(25) =10825a(26) =11726a(27) =12663a(28) =13636a(29) =14645