Triangular numbers whose digits in base 12 are contained in {1,5,7,11}.

Terms

a(0) =1a(1) =91a(2) =1891a(3) =3403a(4) =403651a(5) =4388203a(6) =4468555a(7) =41710411a(8) =201553003a(9) =213283531a(10) =410970115a(11) =428264011a(12) =633021571a(13) =642342403a(14) =703181251a(15) =4913725411a(16) =28007409475a(17) =41103462403a(18) =90151709131a(19) =90294438403a(20) =337594212451a(21) =443352832075