A119222 Triangular numbers composed of digits {5,6,9}.

6, 55, 66, 595, 666, 5565, 5995, 6555, 5656566, 95696695, 95969966995, 956996695656, 6559566959595, 59999565655666, 66555666699966, 555665666566566, 5566956999995566, 9956596655559555, 5555666996669965995, 5555555666655656666556566566566, 55659569595955595555595595599656656

Offset: 1

Author

Giovanni Resta, May 10 2006

Keywords

• nonn
• base

Links

• Giovanni Resta, Tridigital Triangular Numbers.

Crossrefs

Cf. A000217, A053971, A119223. See A119033 for a table of cross-references.

Formula

a(n) = A000217(A119223(n)). - Tyler Busby, Mar 26 2023

Extensions

a(19)-a(21) from Tyler Busby, Mar 26 2023