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 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS 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%10-n^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

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Last modified September 21 09:44 EDT 2020. Contains 337268 sequences. (Running on oeis4.)