A119136 Triangular numbers composed of digits {1,5,8}.

1, 15, 55, 5151, 8515, 581581, 885115, 1188111, 11188815, 51151555, 81581151, 88851115, 851585815, 8888511115, 888885111115, 88888851111115, 8888888511111115, 888888885111111115, 5885188811851888815, 15158585181118581555, 88888888851111111115

Offset: 1

Author

Giovanni Resta, May 10 2006

Keywords

• nonn
• base

Links

• Giovanni Resta, Tridigital Triangular Numbers

Crossrefs

Cf. A000217, A053905, A119137. See A119033 for a table of cross-references.

Formula

a(n) = A000217(A119137(n)). - Michel Marcus, Mar 24 2023

Extensions

a(20)-a(21) from Tyler Busby, Mar 23 2023