A119107 Triangular numbers composed of digits {1,2,8}.

1, 21, 28, 1128, 2211, 8128, 118828, 222111, 821121, 828828, 881128, 1188111, 1828828, 22221111, 28218828, 88811128, 1821212128, 2222211111, 8888111128, 222222111111, 888881111128, 22222221111111, 88888811111128, 1122211112118111, 2222222211111111

Offset: 1

Author

Giovanni Resta, May 10 2006

Keywords

• nonn
• base

Links

• Giovanni Resta, Tridigital Triangular Numbers

Crossrefs

Cf. A000217, A053887, A119108. See A119033 for a table of cross-references.

Formula

a(n) = A000217(A119108(n)). - Michel Marcus, Mar 23 2023

Extensions

a(24)-a(25) from Tyler Busby, Mar 23 2023