Fancy primitive repdigit polygonal numbers (with multiplicity).

Terms

a(0) =6a(1) =9a(2) =22a(3) =55a(4) =66a(5) =88a(6) =111a(7) =111a(8) =222a(9) =333a(10) =444a(11) =555a(12) =666a(13) =777a(14) =888a(15) =6666a(16) =44444a(17) =111111a(18) =111111a(19) =777777a(20) =999999a(21) =111111111a(22) =777777777a(23) =9999999999a(24) =333333333333a(25) =555555555555a(26) =555555555555