A119082 Numbers k such that the k-th triangular number contains only digits {0,5,7}.
10, 100, 124, 375, 1000, 10000, 100000, 1000000, 3924474, 10000000, 100000000, 387492084, 1000000000, 3885885999, 10000000000, 31804089540, 39371996915, 100000000000, 122929061474, 1000000000000, 10000000000000
Offset: 1
Links
- G. Resta, Tridigital Triangular Numbers