A083478 a(n) is the smallest k > 0 such that k*Palindrome(n)+1 is a palindrome.

1, 1, 1, 1, 1, 1, 1, 1, 6, 10, 5, 7, 8, 2, 9, 3, 4, 6, 100, 10, 5, 4, 3, 2, 2, 2, 2, 2, 50, 50, 5, 4, 3, 2, 2, 2, 2, 2, 40, 40, 40, 7, 797, 2, 2, 2, 2, 2, 25, 30, 25, 420, 8, 2, 2, 2, 2, 2, 20, 20, 20, 20, 20, 2, 32, 117, 24, 28, 20, 20, 20, 20, 20, 89, 9, 52, 1870, 150, 20, 20, 20, 20, 20, 85

Offset: 1

Author

Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), May 03 2003

Keywords

• base
• nonn

Examples

			a(11) = 5 because A002113(11) = 22 and 111 = 5*22+1.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..130

Crossrefs

Cf. A083477.

Programs

Mathematica

skpal[n_]:=Module[{k=1},While[!PalindromeQ[k*n+1],k++];k]; skpal/@Select[ Range[ 1000],PalindromeQ] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jul 22 2018 *)

Formula

a(n) = (A083477(n)-1)/A002113(n). a(n) = A082744(A002113(n)). - David Wasserman, Nov 16 2004

Extensions

Corrected and extended by David Wasserman, Nov 16 2004