Triangular numbers whose nonzero digits are all the same.

Terms

a(0) =0a(1) =1a(2) =3a(3) =6a(4) =10a(5) =55a(6) =66a(7) =300a(8) =666a(9) =990a(10) =3003a(11) =5050a(12) =10011a(13) =66066a(14) =500500a(15) =600060a(16) =50005000a(17) =5000050000a(18) =500000500000