A087993 - OEIS

%I #10 Dec 31 2023 16:57:46

%S 45,54,495,594,4356,4545,4995,5454,5895,5985,5994,6534,10890,19602,

%T 20691,29403,30492,39204,40293,43956,45045,49005,49995,50094,54054,

%U 59994,65934,68607,70686,77319,91377,109890,197802,208791,296703,307692

%N Numbers k for which the quotient q(k)=(k+rev(k))/abs(k-rev(k)) is an integer.

%H Giovanni Resta, <a href="/A087993/b087993.txt">Table of n, a(n) for n = 1..500</a>

%e n = 45, rev(n) = 54, q = 99/9 = 9 integer;

%e n = 934065, rev(n) = 560434, q = 1494504/373626 = 4, integer.

%t rev[n_] := FromDigits@ Reverse@ IntegerDigits@ n; Select[Range[10^5], # != (r = rev[#]) && Mod[# + r, # - r] == 0 &] (* _Giovanni Resta_, May 14 2017 *)

%Y Cf. A087994 (the quotients), A118959.

%K base,nonn

%O 1,1

%A _Labos Elemer_, Oct 08 2003