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Search: id:A109880
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| A109880 |
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Numbers n such that n and its digit reversal both are difference of successive cubes. |
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+0
2
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| 1, 7, 19, 91, 127, 721, 919, 14491, 19441, 113491, 177877, 194311, 778771, 1081801, 1188811, 1767169, 1927207, 1946491, 7027291, 9617671, 16056847, 74775169, 74865061, 96157747, 129869461, 164968921, 167828761, 180676081, 189202267, 757333297, 762202981, 792333757, 1917766117, 7116677191
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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A subsequence of A109879.
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EXAMPLE
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19 = 3^3-2^3 and 91 = 6^3-5^3.
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MATHEMATICA
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okQ[x_]:=Module[{revx=FromDigits[Reverse[IntegerDigits[x]]]}, And@@(And@@IntegerQ/@(n/.Solve[1+3n+3n^2==x, n])&&And@@IntegerQ/@(n/.Solve[1+3n+3n^2==revx, n]))] Select[Range[90000], okQ] - Harvey P. Dale (hpd1(AT)nyu.edu), Aug 06 2007
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CROSSREFS
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Cf. A109879.
Sequence in context: A155390 A088988 A109879 this_sequence A084603 A088883 A026574
Adjacent sequences: A109877 A109878 A109879 this_sequence A109881 A109882 A109883
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KEYWORD
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base,nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Jul 10 2005
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EXTENSIONS
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More terms from Harvey P. Dale (hpd1(AT)nyu.edu), Aug 06 2007
23 more terms from Donovan Johnson (donovan.johnson(AT)yahoo.com), Feb 21 2008
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