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A119035
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Triangular numbers composed of digits {0,1,3}.
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2
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1, 3, 10, 300, 3003, 10011, 303031, 1010331, 1030330, 1313010, 101111310, 113033130, 1033010331, 11031100311, 11033031331, 31031010003, 111111101310, 313313301003, 10113301131300, 3330130113300130003, 1113011003000100031311, 11013033300110103011310
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OFFSET
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1,2
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LINKS
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Table of n, a(n) for n=1..22.
Giovanni Resta, Tridigital Triangular Numbers.
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FORMULA
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a(n) = A000217(A119036(n)). - Tyler Busby, Mar 31 2023
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MATHEMATICA
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Rest[Select[FromDigits/@Tuples[{0, 1, 3}, 10], IntegerQ[(Sqrt[8 # + 1] - 1)/2] &]] (* Vincenzo Librandi, Dec 18 2015 *)
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PROG
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(Magma) [t: n in [1..2*10^7] | Set(Intseq(t)) subset {0, 1, 3} where t is n*(n+1) div 2]; // Vincenzo Librandi, Dec 18 2015
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CROSSREFS
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Cf. A000217, A119036. See A119033 for a table of cross-references.
Sequence in context: A270553 A308657 A156193 * A359554 A004100 A349894
Adjacent sequences: A119032 A119033 A119034 * A119036 A119037 A119038
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KEYWORD
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nonn,base,changed
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AUTHOR
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Giovanni Resta, May 10 2006
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EXTENSIONS
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a(21)-a(22) from Tyler Busby, Mar 22 2023
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STATUS
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approved
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