The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A072969 Least k > 0 such that the last digit of k^n is the same as the last digit of n^k. 0

%I #7 Mar 30 2012 18:39:04

%S 1,2,3,2,5,4,7,4,9,10,1,4,7,4,5,2,3,2,9,10,1,2,3,2,5,4,7,4,9,10,1,4,7,

%T 4,5,2,3,2,9,10,1,2,3,2,5,4,7,4,9,10,1,4,7,4,5,2,3,2,9,10,1,2,3,2,5,4,

%U 7,4,9,10,1,4,7,4,5,2,3,2,9,10,1,2,3,2,5,4,7,4,9,10,1,4,7,4,5,2,3,2,9

%N Least k > 0 such that the last digit of k^n is the same as the last digit of n^k.

%F a(n) is a periodic sequence with period (1, 2, 3, 2, 5, 4, 7, 4, 9, 10, 1, 4, 7, 4, 5, 2, 3, 2, 9, 10, ) of length 20

%o (PARI) a(n)=if(n<0,0,k=1; while(abs(k^n%10-n^k%10)>0,s++); s)

%K base,easy,nonn

%O 1,2

%A _Benoit Cloitre_, Aug 13 2002

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 24 22:14 EDT 2023. Contains 365582 sequences. (Running on oeis4.)