A119127 Numbers k such that the k-th triangular number contains only digits {1,4,7}.

1, 18, 38, 58, 15306, 28893, 3851686, 595216169886, 53248694146381, 536869582203620058, 14927275335718688666

Offset

1,2

Links

Table of n, a(n) for n=1..11.

Giovanni Resta, Tridigital Triangular Numbers.

Crossrefs

Cf. A000217, A079654. See A119034 for a table of cross-references.

Sequence in context: A041646 A244412 A114698 * A190739 A084585 A132761

Adjacent sequences: A119124 A119125 A119126 * A119128 A119129 A119130

Keyword

nonn,base,more

Author

Giovanni Resta, May 10 2006

Extensions

a(10)-a(11) from Tyler Busby, Mar 31 2023

Status

approved