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Search: id:A109879
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| A109879 |
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Numbers n such that n and its digit reversal R(n) both are difference of positive cubes. |
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+0
5
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| 7, 19, 91, 127, 721, 919, 999, 1385, 1727, 3159, 4376, 5409, 5831, 6734, 7271, 9045, 9513, 10647, 11824, 12691, 14491, 15967, 16939, 19441, 19621, 25352, 26973, 27872, 28737, 29783, 31213, 35163, 35929, 36153, 37962, 37973, 38656, 38792, 39636
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Numbers n such that n and R(n) are both of the form a^3-b^3 with a > b > 0.
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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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t1 = Select[ Union[ Flatten[ Table[n^3 - m^3, {n, 185}, {m, 0, n - 1}]]], # < 10^5 && Mod[ #, 10] != 0 &]; t2 = FromDigits /@ Reverse /@ IntegerDigits /@ t1; Take[ Intersection[t1, t2], 40] (from Robert G. Wilson v (rgwv(at)rgwv.com), Jul 14 2005)
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CROSSREFS
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Cf. A109880.
Sequence in context: A111011 A062551 A088988 this_sequence A109880 A084603 A088883
Adjacent sequences: A109876 A109877 A109878 this_sequence A109880 A109881 A109882
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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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Edited and extended by Robert G. Wilson v (rgwv(at)rgwv.com), Jul 14 2005
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