A119142 - OEIS

%I #11 Mar 24 2023 03:03:08

%S 1,6,66,666,861,116886,1188111,8166861,681118686,8186688861,

%T 181886818816,616886668881,1611611188111,6188181818668868161,

%U 8188686181116816661,61116116118118668181,686168618118116111616,1118166618111681811816,66861818861688166881668181

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

%H Giovanni Resta, <a href="http://www.numbersaplenty.com/tr/tr168.html">Tridigital Triangular Numbers</a>

%F a(n) = A000217(A119143(n)). - _Michel Marcus_, Mar 24 2023

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

%K nonn,base

%O 1,2

%A _Giovanni Resta_, May 10 2006

%E a(18)-a(19) from _Tyler Busby_, Mar 23 2023