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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

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

LINKS

Table of n, a(n) for n=1..39.

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

Cf. A109880.

Sequence in context: A300556 A267378 A088988 * A109880 A245489 A084603

Adjacent sequences:  A109876 A109877 A109878 * A109880 A109881 A109882

KEYWORD

base,nonn

AUTHOR

Amarnath Murthy, Jul 10 2005

EXTENSIONS

Edited and extended by Robert G. Wilson v, Jul 14 2005

STATUS

approved

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Last modified July 6 23:01 EDT 2020. Contains 335484 sequences. (Running on oeis4.)