Numbers k such that the k-th triangular number contains only digits {1,4,9}.

A119131

Numbers k such that the k-th triangular number contains only digits {1,4,9}.

Terms

    a(0) =1a(1) =13a(2) =313a(3) =538a(4) =13741a(5) =43386a(6) =48886a(7) =991886a(8) =141415133a(9) =2880781113a(10) =4721227413a(11) =19567549258a(12) =538423521386

External references