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

1,1

Links

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

Giovanni Resta, Tridigital Triangular Numbers

Formula

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

Crossrefs

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

Sequence in context: A243719 A156237 A119142 * A119100 A119176 A155630

Adjacent sequences: A119088 A119089 A119090 * A119092 A119093 A119094

Keyword

nonn,base

Author

Giovanni Resta, May 10 2006

Extensions

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

Status

approved