A119091 Triangular numbers composed of digits {0,6,9}.

6, 66, 666, 990, 66066, 69006, 600060, 609960, 690900, 969606666, 60690060606, 96960006066, 66999966009690066, 96606660096609006, 6900969009006996666, 9906090099969060666906, 6666999999969090090996690, 60969009000966690090069999000606, 660690009096060660069069660609900960960

Offset: 1

Author

Giovanni Resta, May 10 2006

Keywords

• nonn
• base

Links

• Giovanni Resta, Tridigital Triangular Numbers

Crossrefs

Cf. A000217, A058452, A119092. See A119033 for a table of cross-references.

Formula

a(n) = A000217(A119092(n)). - Tyler Busby, Mar 26 2023

Extensions

a(18)-a(19) from Tyler Busby, Mar 26 2023