A119156 Triangular numbers composed of digits {2,3,8}.

3, 28, 3828, 828828, 388333828828, 223832333328828, 332828222833288828828, 28388332838238232223328828

Offset: 1

Author

Giovanni Resta, May 10 2006

Keywords

• nonn
• base
• more

Comments

a(9) > 10^45. - Tyler Busby, Mar 29 2023

Links

• Giovanni Resta, Tridigital Triangular Numbers.

Crossrefs

Cf. A000217, A119157. See A119033 for a table of cross-references.

Programs

Python

klimit = 10**6
A000217 = (k*(k+1)//2 for k in range(klimit)) # generator
print([m for m in A000217 if set(str(m)) <= set("238")]) # Michael S. Branicky, Mar 28 2021

Formula

a(n) = A000217(A119157(n)). - Tyler Busby, Mar 29 2023