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Search: id:A072969
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| A072969 |
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Least k > 0 such that the last digit of k^n is the same as the last digit of n^k. |
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+0 1
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| 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; listen)
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OFFSET
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1,2
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FORMULA
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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
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PROGRAM
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(PARI) a(n)=if(n<0, 0, k=1; while(abs(k^n%10-n^k%10)>0, s++); s)
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CROSSREFS
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Sequence in context: A067316 A127433 A055573 this_sequence A139712 A075365 A075274
Adjacent sequences: A072966 A072967 A072968 this_sequence A072970 A072971 A072972
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KEYWORD
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base,easy,nonn
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AUTHOR
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Benoit Cloitre (benoit7848c(AT)orange.fr), Aug 13 2002
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