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A119138
Triangular numbers composed of digits {1,5,9}.
2
1, 15, 55, 91, 595, 5151, 5995, 9591, 1511191, 51151555, 195911115, 511151999595, 519191199555, 555595555515, 595151955555, 591915955919511, 15995115959551911, 159955559191119511, 9199995595111955111955555, 1559111919555519991599911911
OFFSET
1,2
FORMULA
a(n) = A000217(A119139(n)). - Tyler Busby, Mar 28 2023
CROSSREFS
Cf. A000217, A119139. See A119033 for a table of cross-references.
Sequence in context: A225509 A235533 A039369 * A043192 A043972 A226196
KEYWORD
nonn,base
AUTHOR
Giovanni Resta, May 10 2006
EXTENSIONS
a(20) from Tyler Busby, Mar 28 2023
STATUS
approved