A119226 Triangular numbers composed of digits {5,7,9}.

55, 595, 5995, 7779577597795, 9775779559755, 57575799959759975575, 77777755779995957575, 7577959575775997959995995979795

Offset: 1

Author

Giovanni Resta, May 10 2006

Keywords

• nonn
• base
• more

Comments

a(9) > 10^40. - Tyler Busby, Mar 29 2023

Links

• Giovanni Resta, Tridigital Triangular Numbers.

Crossrefs

Cf. A000217, A119227. See A119033 for a table of cross-references.

Formula

a(n) = A000217(A119227(n)). - Michel Marcus, Mar 27 2023