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A119216
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Triangular numbers composed of digits {4,7,8}.
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2
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78, 8778, 448878, 887778, 7478778, 88877778, 8888777778, 44847878778, 747488474778, 888887777778, 88888877777778, 8888888777777778, 888888887777777778, 7778777484477877878, 88888888877777777778
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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LINKS
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Table of n, a(n) for n=1..15.
G. Resta, Tridigital Triangular Numbers
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MATHEMATICA
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Table[Select[FromDigits/@Tuples[{4, 7, 8}, n], OddQ[Sqrt[8#+1]]&], {n, 20}]//Flatten (* The program will take a long time to run. *) (* Harvey P. Dale, Oct 15 2017 *)
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CROSSREFS
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Cf. A000217, A053963, A119217. See A119033 for a table of cross-references.
Sequence in context: A268023 A268016 A077694 * A119236 A126998 A299712
Adjacent sequences: A119213 A119214 A119215 * A119217 A119218 A119219
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KEYWORD
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nonn,base
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AUTHOR
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Giovanni Resta, May 10 2006
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STATUS
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approved
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