A119149 Numbers k such that the k-th triangular number contains only digits {1,7,9}.

1, 13, 18, 58, 586, 1258, 58613, 1350538, 1414213, 59517693, 1398413386, 5996665693, 119976657489461

Offset

1,2

Comments

Next term exceeds 1.4*10^16.

Links

Table of n, a(n) for n=1..13.

G. Resta, Tridigital Triangular Numbers

Crossrefs

Cf. A000217, A119148. See A119034 for a table of cross-references.

Sequence in context: A318348 A197704 A218626 * A217658 A372763 A236999

Adjacent sequences: A119146 A119147 A119148 * A119150 A119151 A119152

Keyword

nonn,base,more

Author

Giovanni Resta, May 10 2006

Status

approved