

A109879


Numbers n such that n and its digit reversal R(n) both are difference of positive cubes.


4



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
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OFFSET

1,1


COMMENTS

Numbers n such that n and R(n) are both of the form a^3b^3 with a > b > 0.


LINKS



EXAMPLE

19 = 3^3  2^3 and 91 = 6^3  5^3.


MATHEMATICA

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] (* Robert G. Wilson v, Jul 14 2005 *)


CROSSREFS



KEYWORD

base,nonn


AUTHOR



EXTENSIONS



STATUS

approved



