A068822 a(n) = gcd(n,c(n)), where c(n) is the 10's complement of n.

1, 2, 1, 2, 5, 2, 1, 2, 1, 10, 1, 4, 1, 2, 5, 4, 1, 2, 1, 20, 1, 2, 1, 4, 25, 2, 1, 4, 1, 10, 1, 4, 1, 2, 5, 4, 1, 2, 1, 20, 1, 2, 1, 4, 5, 2, 1, 4, 1, 50, 1, 4, 1, 2, 5, 4, 1, 2, 1, 20, 1, 2, 1, 4, 5, 2, 1, 4, 1, 10, 1, 4, 1, 2, 25, 4, 1, 2, 1, 20, 1, 2

Offset: 1

Author

Amarnath Murthy, Mar 08 2002

Keywords

• nonn
• base
• easy

Examples

			a(45) = 5 as 10's complement of 45 is 100-45 = 55 and (45,55) = 5.
		

Links

• Alois P. Heinz, Table of n, a(n) for n = 1..9999

Crossrefs

Cf. A089186, A178914.

Programs

Maple

a:=n-> igcd((10^length(n)-n), n):
seq(a(n), n=1..100);  # Alois P. Heinz, Sep 22 2015

Mathematica

GCD[#, 10^(IntegerLength[#]) - #] & /@ Range[82] (* Jayanta Basu, Aug 07 2013 *)

Formula

a(n) = gcd(n,A089186(n)) = gcd(n,A178914(n)). - Alois P. Heinz, Nov 05 2018