**a(n+1) = if {a(k):1<=k<=n} is a permutation of [1:n] then 2*a(n) else a(n)-1.**

*1, 2, 4, 3, 6, 5, 10, 9, 8, 7, 14, 13, 12, 11, 22, 21, 20, 19, 18, 17, 16, 15, 30, 29, 28, 27*

*2 seqfan posts*

Index of A-numbers in seqfan: by ascending order by month by frequency by keyword

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