A119120 Numbers k such that the k-th triangular number contains only digits {1,3,8}.

1, 2, 421, 1541, 8753, 150421, 12914246, 1327696379533, 4034385661121, 605166395826533, 16360402306368458, 249752330575267378

Offset

1,2

Comments

Next term exceeds 4.4*10^18.

Links

Table of n, a(n) for n=1..12.

G. Resta, Tridigital Triangular Numbers

Crossrefs

Cf. A000217, A119119. See A119034 for a table of cross-references.

Sequence in context: A365520 A080392 A154541 * A373552 A332142 A109931

Adjacent sequences: A119117 A119118 A119119 * A119121 A119122 A119123

Keyword

nonn,base,more

Author

Giovanni Resta, May 10 2006

Extensions

Two more terms from Max Alekseyev, May 12 2009

Status

approved