A119118 Numbers k such that the k-th triangular number contains only digits {1,3,7}.

1, 2, 18, 58, 1853, 5853, 1620578, 485216058, 1243473981, 2747265466, 595277030253, 789599540493, 2573455929746, 48450258487106, 393226940373453389658

Offset

1,2

Links

Table of n, a(n) for n=1..15.

Giovanni Resta, Tridigital Triangular Numbers

Crossrefs

Cf. A000217, A119117. See A119034 for a table of cross-references.

Sequence in context: A058794 A114109 A085293 * A213820 A078837 A232155

Adjacent sequences: A119115 A119116 A119117 * A119119 A119120 A119121

Keyword

nonn,base,more

Author

Giovanni Resta, May 10 2006

Extensions

a(15) from Bert Dobbelaere, Mar 15 2026

Status

approved