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A119204
Triangular numbers composed of digits {4,5,7}.
2
45, 55, 5747745, 744574755, 77545447574475, 4745745457757444544544575, 44477447457545755547775754555, 547457575775574544754447747777455
OFFSET
1,1
COMMENTS
a(8) > 10^40. - Tyler Busby, Mar 28 2023
FORMULA
a(n) = A000217(A119205(n)). - Jon E. Schoenfield, Mar 27 2023
CROSSREFS
Cf. A000217, A053951, A119205. See A119033 for a table of cross-references.
Sequence in context: A068812 A119071 A119158 * A119206 A060463 A206024
KEYWORD
nonn,base,more
AUTHOR
Giovanni Resta, May 10 2006
EXTENSIONS
a(8) from Tyler Busby, Mar 28 2023
STATUS
approved