login
Smallest k such that n*k-1 is a palindrome, or 0 if no such number exists.
2

%I #10 Jun 16 2022 17:44:26

%S 1,1,1,1,1,1,1,1,1,1,12,1,6,4,3,7,2,9,8,5,13,6,1,8,4,3,6,2,7,31,15,6,

%T 4,1,13,9,36,4,2,23,17,13,4,3,1,11,20,4,13,2,2,7,170,3,9,1,11,92,6,16,

%U 2,15,13,3,7,2,1,11,37,13,2,8,9,18,126,2,791,1,11,12,2,9,5,41

%N Smallest k such that n*k-1 is a palindrome, or 0 if no such number exists.

%C Conjecture: No entry is zero. For every n there exists a k such that n*k-1 is a palindrome.

%e a(13)=6 as 13*6-1=77, a palindrome.

%t skpal[n_]:=Module[{k=1},While[!PalindromeQ[k*n-1],k++];k]; Array[skpal,90] (* _Harvey P. Dale_, Jun 16 2022 *)

%K base,nonn

%O 1,11

%A _Amarnath Murthy_ and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Jul 03 2003

%E More terms from _Jason Earls_, Jul 08 2003