A119219 Numbers k such that the k-th triangular number contains only digits {5,6,7}.

3, 10, 11, 36, 105, 114, 3363, 3369, 3648, 10636, 1073010, 1164274, 33336636, 33336696, 107290789, 1063736505, 3887841963, 3333333366663363, 389041582810258897588, 114522117223501116660114

Offset

1,1

Comments

a(19) exceeds 1.4*10^16.

Links

Table of n, a(n) for n=1..20.

Giovanni Resta, Tridigital Triangular Numbers

Crossrefs

Cf. A000217, A119218. See A119034 for a table of cross-references.

Sequence in context: A119165 A119080 A119221 * A125569 A201156 A309525

Adjacent sequences: A119216 A119217 A119218 * A119220 A119221 A119222

Keyword

nonn,base,more

Author

Giovanni Resta, May 10 2006

Extensions

a(19)-a(20) from Bert Dobbelaere, Mar 15 2026

Status

approved