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A117985
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Pentagonal numbers with only odd digits.
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2
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1, 5, 35, 51, 117, 715, 1335, 1717, 3151, 3577, 5551, 5735, 7315, 7957, 15555, 55777, 71177, 73151, 99717, 135751, 171197, 319935, 331115, 335357, 371757, 377755, 711737, 755795, 935755, 1111551, 1517551, 1553977, 1739355, 1911397, 1993537, 3131315, 3311551
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OFFSET
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1,2
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LINKS
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MATHEMATICA
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Select[Table[n*(3*n - 1)/2, {n, 0, 3000}], AllTrue[IntegerDigits[#], OddQ] &] (* Amiram Eldar, Feb 06 2021 *)
Select[PolygonalNumber[5, Range[1500]], AllTrue[IntegerDigits[#], OddQ]&] (* Harvey P. Dale, Oct 17 2021 *)
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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Luc Stevens (lms022(AT)yahoo.com), May 03 2006
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EXTENSIONS
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STATUS
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approved
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