A119200 Triangular numbers composed of digits {3,7,8}.

3, 78, 378, 8778, 887778, 88877778, 8787733878, 8888777778, 73778888778, 888887777778, 8883333788878, 37383337333378, 88888877777778, 8888888777777778, 888888887777777778, 88888888877777777778, 8888888888777777777778, 887783783833373788333378

Offset: 1

Author

Giovanni Resta, May 10 2006

Keywords

• nonn
• base

Links

• Giovanni Resta, Tridigital Triangular Numbers.

Crossrefs

Cf. A000217, A119201. See A119033 for a table of cross-references.

Formula

a(n) = A000217(A119201(n)). - Tyler Busby, Mar 24 2023

Extensions

a(17)-a(18) from Tyler Busby, Mar 24 2023