A119167 Numbers k such that the k-th triangular number contains only digits {2,5,7}.

10, 74, 714, 1074, 1070285, 2270474, 1206047449, 67189697949, 324723752049, 23346424812260967349

Offset: 1

Author

Giovanni Resta, May 10 2006

Keywords

• nonn
• base
• more

Links

• Giovanni Resta, Tridigital Triangular Numbers.

Crossrefs

Cf. A000217, A119166. See A119034 for a table of cross-references.

Extensions

a(10) from Tyler Busby, Mar 31 2023