|
%I #11 Mar 27 2023 03:33:43
%S 6,66,78,666,6786,8778,676866,887778,88877778,8888777778,888887777778,
%T 7768686676878,68886888677778,88888877777778,8888888777777778,
%U 888888887777777778,88888888877777777778,8888888888777777777778,86686767888666878787778,786777868668667866767766
%N Triangular numbers composed of digits {6,7,8}.
%H Giovanni Resta, <a href="http://www.numbersaplenty.com/tr/tr678.html">Tridigital Triangular Numbers</a>.
%F a(n) = A000217(A119231(n)). - _Tyler Busby_, Mar 26 2023
%Y Cf. A000217, A119231. See A119033 for a table of cross-references.
%K nonn,base
%O 1,1
%A _Giovanni Resta_, May 10 2006
%E a(19)-a(20) from _Tyler Busby_, Mar 26 2023
|
