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A109879 Numbers n such that n and its digit reversal R(n) both are difference of positive cubes. 4

%I

%S 7,19,91,127,721,919,999,1385,1727,3159,4376,5409,5831,6734,7271,9045,

%T 9513,10647,11824,12691,14491,15967,16939,19441,19621,25352,26973,

%U 27872,28737,29783,31213,35163,35929,36153,37962,37973,38656,38792,39636

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

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

%e 19 = 3^3 - 2^3 and 91 = 6^3 - 5^3.

%t 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 *)

%Y Cf. A109880.

%K base,nonn

%O 1,1

%A _Amarnath Murthy_, Jul 10 2005

%E Edited and extended by _Robert G. Wilson v_, Jul 14 2005

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Last modified January 28 12:29 EST 2022. Contains 350656 sequences. (Running on oeis4.)