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Least positive palindromic multiple of n, or 0 if none exists.
7

%I #28 Feb 10 2023 15:51:37

%S 0,1,2,3,4,5,6,7,8,9,0,11,252,494,252,525,272,272,252,171,0,252,22,

%T 161,696,525,494,999,252,232,0,434,2112,33,272,525,252,111,494,585,0,

%U 656,252,989,44,585,414,141,2112,343,0,969,676,212,27972,55,616,171,232,767,0,26962

%N Least positive palindromic multiple of n, or 0 if none exists.

%C Smallest positive palindrome divisible by n, or 0 if no such palindrome exists (which happens iff n is a multiple of 10). - _N. J. A. Sloane_, Apr 04 2019

%C The existence of palindromic multiples is a corollary of the theorem that an arithmetic progression with initial term c and a positive common difference d contains infinitely many palindromic numbers unless both of these numbers are multiples of 10. - M. Harminc (harminc(AT)duro.science.upjs.sk), Jul 14 2000

%H Giovanni Resta, <a href="/A020485/b020485.txt">Table of n, a(n) for n = 0..10000</a> (first 8181 terms from N. J. A. Sloane)

%H Ely Golden, <a href="/A020485/a020485_1.py.txt">Python program for generating terms of this sequence</a>

%H M. Harminc and R. Sotak, <a href="https://www.fq.math.ca/Scanned/36-3/harminc.pdf">Palindromic numbers in arithmetic progressions</a>, Fibonacci Quarterly Journal, Jun-Jul (1998), pp. 259-262.

%F a(n) = n*A050782(n). - _Michel Marcus_, Jan 22 2019

%Y Cf. A002113, A050782.

%K nonn,base

%O 0,3

%A _David W. Wilson_

%E a(0)=0 added by _N. J. A. Sloane_, Apr 04 2019