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%I #13 Mar 13 2023 07:22:54
%S 1,2,3,4,12,13,14,16,17,19,21,23,24,25,26,28,31,37,42,47,49,102,103,
%T 109,133,147,159,166,197,199,201,204,208,218,233,247,295,296,298,301,
%U 397,402,497,499,1002,1003,1009,1019,1029,1038,1039,1049,1059,1069
%N Numbers that have a larger multiple which differs in just one digit from its reverse.
%C From _Robert Israel_, Mar 12 2023: (Start)
%C The number and its multiple must have the same number of digits.
%C Infinite families of terms include 10^n + 2, 10^n + 3, 10^n + 9, (4*10^n - 1)/3, 1.5*10^n + 9, (5*10^n - 1)/3, 2*10^n - 3, 2*10^n - 1, 2*10^n + 1, 2*10^n + 4, 2*10^n+8, 3*10^n - 5, 3*10^n - 4, 3*10^n - 2, 3*10^n + 1, (7*10^n - 1)/3, 4*10^n - 3, 4*10^n + 2, 5*10^n - 3, 5*10^n - 1. (End)
%H Robert Israel, <a href="/A062946/b062946.txt">Table of n, a(n) for n = 1..215</a>
%e 1997*3=5991, which differs in just one digit from 7991, the reverse of 1997.
%p filter:= proc(n) local L, d, m, Lp;
%p L:= ListTools:-Reverse(convert(n,base,10));
%p d:= nops(L)-1;
%p for m from 2*n by n while ilog10(m) = d do
%p Lp:= convert(m,base,10);
%p if nops(subs(0=NULL, L-Lp) = 1 then return true fi;
%p od;
%p false
%p end proc:
%p select(filter, [seq($ (10^d) .. (5*10^d-1), d=0..4)]); # _Robert Israel_, Mar 12 2023
%K base,nonn
%O 1,2
%A _Erich Friedman_, Jul 21 2001
%E Offset changed by _Robert Israel_, Mar 12 2023
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