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A119081
Triangular numbers composed of digits {0,5,7}.
2
55, 5050, 7750, 70500, 500500, 50005000, 5000050000, 500000500000, 7700750050575, 50000005000000, 5000000050000000, 75075057775077570, 500000000500000000, 7550055000555057000, 50000000005000000000, 505750055750070750570, 775077070557070757070
OFFSET
1,1
FORMULA
a(n) = A000217(A119082(n)). - Michel Marcus, Mar 23 2023
CROSSREFS
Cf. A000217, A119082. See A119033 for a table of cross-references.
Sequence in context: A103918 A013537 A056567 * A119051 A119083 A037156
KEYWORD
nonn,base
AUTHOR
Giovanni Resta, May 10 2006
EXTENSIONS
a(16)-a(17) from Tyler Busby, Mar 23 2023
STATUS
approved