A119069 - OEIS

%I #9 Mar 22 2023 18:27:27

%S 3,300,903,990,3003,33930,39903,339900,930930,39033030,990903903,

%T 3909003990,3993990000,33003300903,39999939903,90993993300,

%U 3390003090090,99990099000330,90009933903093903,399939399933939330,303300903903330099003,3309000900300303999300

%N Triangular numbers composed of digits {0,3,9}.

%H Giovanni Resta, <a href="http://www.numbersaplenty.com/tr/tr039.html">Tridigital Triangular Numbers</a>

%F a(n) = A000217(A119070(n)). - _Michel Marcus_, Mar 22 2023

%Y Cf. A000217, A058434, A119070. See A119033 for a table of cross-references.

%K nonn,base

%O 1,1

%A _Giovanni Resta_, May 10 2006

%E a(21)-a(22) from _Tyler Busby_, Mar 22 2023