Triangular numbers composed of digits {1,5,8}.

Terms

a(0) =1a(1) =15a(2) =55a(3) =5151a(4) =8515a(5) =581581a(6) =885115a(7) =1188111a(8) =11188815a(9) =51151555a(10) =81581151a(11) =88851115a(12) =851585815a(13) =8888511115a(14) =888885111115