A119210 Triangular numbers composed of digits {4,6,7}.

6, 66, 666, 476776, 764466, 4646676, 464774774646, 667474767766464747666467446, 7666777767444444644744476476, 44774674766666676747766477446

Offset: 1

Author

Giovanni Resta, May 10 2006

Keywords

• nonn
• base
• more

Comments

a(11) > 10^40. - Tyler Busby, Mar 29 2023

Links

• Giovanni Resta, Tridigital Triangular Numbers.

Crossrefs

Cf. A000217, A053957, A119211. See A119033 for a table of cross-references.

Formula

a(n) = A000217(A119211(n)). - Michel Marcus, Mar 27 2023