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

1,2

Links

Table of n, a(n) for n=1..19.

Giovanni Resta, Tridigital Triangular Numbers

Formula

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

Crossrefs

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

Sequence in context: A043041 A243719 A156237 * A119091 A119100 A119176

Adjacent sequences: A119139 A119140 A119141 * A119143 A119144 A119145

Keyword

nonn,base

Author

Giovanni Resta, May 10 2006

Extensions

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

Status

approved