A119166 Triangular numbers composed of digits {2,5,7}.

55, 2775, 255255, 577275, 572755525755, 2577527227575, 727275225222727525, 2257227755272522252275, 52722757572552577725225, 272527775757277272275522727772752527575

Offset: 1

Author

Giovanni Resta, May 10 2006

Keywords

• nonn
• base
• more

Comments

a(11) > 10^40. - Tyler Busby, Mar 28 2023

Links

• Giovanni Resta, Tridigital Triangular Numbers.

Crossrefs

Cf. A000217, A030485, A119167. See A119033 for a table of cross-references.

Formula

a(n) = A000217(A119167(n)). - Tyler Busby, Mar 28 2023

Extensions

a(10) from Tyler Busby, Mar 28 2023