**a(1)=1; for n>1, a(n)=a(n-1)-4 if n is already in the sequence, a(n)=a(n-1)+5 otherwise.**

*1, 6, 11, 16, 21, 17, 22, 27, 32, 37, 33, 38, 43, 48, 53, 49, 45, 50, 55, 60, 56, 52, 57*

*5 seqfan posts*

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

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