A119139 Numbers k such that the k-th triangular number contains only digits {1,5,9}.

1, 5, 10, 13, 34, 101, 109, 138, 1738, 10114, 19794, 1011090, 1019010, 1054130, 1091010, 34406858, 178858133, 565606858, 4289521091010, 55841058721258

Offset

1,2

Comments

Next term exceeds 1.4*10^16.

Links

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

G. Resta, Tridigital Triangular Numbers

Crossrefs

Cf. A000217, A119138. See A119034 for a table of cross-references.

Sequence in context: A321558 A328667 A317966 * A313451 A164889 A173553

Adjacent sequences: A119136 A119137 A119138 * A119140 A119141 A119142

Keyword

nonn,base,more

Author

Giovanni Resta, May 10 2006

Status

approved