A119230 Triangular numbers composed of digits {6,7,8}.

6, 66, 78, 666, 6786, 8778, 676866, 887778, 88877778, 8888777778, 888887777778, 7768686676878, 68886888677778, 88888877777778, 8888888777777778, 888888887777777778, 88888888877777777778, 8888888888777777777778, 86686767888666878787778, 786777868668667866767766

Offset

1,1

Links

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

Giovanni Resta, Tridigital Triangular Numbers.

Formula

a(n) = A000217(A119231(n)). - Tyler Busby, Mar 26 2023

Crossrefs

Cf. A000217, A119231. See A119033 for a table of cross-references.

Sequence in context: A284067 A137121 A110222 * A372547 A122780 A153514

Adjacent sequences: A119227 A119228 A119229 * A119231 A119232 A119233

Keyword

nonn,base

Author

Giovanni Resta, May 10 2006

Extensions

a(19)-a(20) from Tyler Busby, Mar 26 2023

Status

approved