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Search: id:A079654
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| A079654 |
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Triangular numbers using only the straight digits 1, 4 and 7. |
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+0
3
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| 1, 171, 741, 1711, 117144471, 417417171, 7417744447141, 177141144447177414711441, 1417711714147441711474771771
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Probably finite.
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LINKS
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G. Resta, Tridigital Triangular Numbers
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MATHEMATICA
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Do[ If[ Union[ Join[ IntegerDigits[n(n + 1)/2], {1, 4, 7}]] == {1, 4, 7}, Print[n(n + 1)/2]], {n, 0, 3*10^7}]
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CROSSREFS
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Cf. A000217, A028373, A053899, A119127. See A119033 for a table of cross-references.
Sequence in context: A043407 A031691 A158220 this_sequence A036518 A016058 A152926
Adjacent sequences: A079651 A079652 A079653 this_sequence A079655 A079656 A079657
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KEYWORD
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base,nonn
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AUTHOR
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Shyam Sunder Gupta (guptass(AT)rediffmail.com), Jan 23 2003
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EXTENSIONS
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Edited and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 24 2003
More terms from Giovanni Resta (g.resta(AT)iit.cnr.it), May 10 2006
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