A119142 Triangular numbers composed of digits {1,6,8}.

1, 6, 66, 666, 861, 116886, 1188111, 8166861, 681118686, 8186688861, 181886818816, 616886668881, 1611611188111, 6188181818668868161, 8188686181116816661, 61116116118118668181, 686168618118116111616, 1118166618111681811816, 66861818861688166881668181

Offset: 1

Author

Giovanni Resta, May 10 2006

Keywords

• nonn
• base

Links

• Giovanni Resta, Tridigital Triangular Numbers

Crossrefs

Cf. A000217, A053909, A119143. See A119033 for a table of cross-references.

Formula

a(n) = A000217(A119143(n)). - Michel Marcus, Mar 24 2023

Extensions

a(18)-a(19) from Tyler Busby, Mar 23 2023