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A119178
Triangular numbers composed of digits {2,7,8}.
2
28, 78, 2278, 8778, 222778, 828828, 887778, 8272278, 22227778, 88278828, 88877778, 2222277778, 2882872278, 8882778828, 8888777778, 222222777778, 888827778828, 888887777778, 22222227777778, 88888277778828, 88888877777778, 228887828777278, 272277272227278
OFFSET
1,1
FORMULA
a(n) = A000217(A119179(n)). - Michel Marcus, Mar 22 2023
CROSSREFS
Cf. A000217, A119179. See A119033 for a table of cross-references.
Sequence in context: A044166 A044547 A268733 * A161935 A039415 A043238
KEYWORD
nonn,base
AUTHOR
Giovanni Resta, May 10 2006
EXTENSIONS
a(21)-a(23) from Tyler Busby, Mar 22 2023
STATUS
approved