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A079654
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Triangular numbers using only the straight digits 1, 4 and 7.
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2
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OFFSET
| 1,2
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COMMENTS
| Probably finite.
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LINKS
| G. Resta, Tridigital Triangular Numbers
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MATHEMATICA
| 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
| Cf. A000217, A028373, A053899, A119127. See A119033 for a table of cross-references.
Sequence in context: A043407 A031691 A158220 * A036518 A187133 A185838
Adjacent sequences: A079651 A079652 A079653 * A079655 A079656 A079657
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KEYWORD
| base,nonn
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AUTHOR
| Shyam Sunder Gupta (guptass(AT)rediffmail.com), Jan 23 2003
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EXTENSIONS
| 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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