a(n) is the smallest n-gonal number whose sum of digits is n.

Terms

a(0) =3a(1) =4a(2) =5a(3) =6a(4) =7a(5) =8a(6) =9a(7) =370a(8) =506a(9) =156a(10) =238a(11) =671a(12) =726a(13) =88a(14) =836a(15) =585a(16) =775a(17) =7337a(18) =5268a(19) =8149a(20) =8555a(21) =8961a(22) =9367a(23) =9773a(24) =15786a(25) =9856a(26) =91964a(27) =65757a(28) =89428a(29) =179960