

A072969


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


0



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, 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, 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
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OFFSET

1,2


LINKS

Table of n, a(n) for n=1..99.


FORMULA

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


PROG

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


CROSSREFS

Sequence in context: A195637 A181861 A212831 * A139712 A175856 A075365
Adjacent sequences: A072966 A072967 A072968 * A072970 A072971 A072972


KEYWORD

base,easy,nonn


AUTHOR

Benoit Cloitre, Aug 13 2002


STATUS

approved



