**a(1)=1. a(n) = the smallest integer > a(n-1) where both a(n)-1 and a(n)+1 are coprime to all earlier terms of the sequence.**

*1, 2, 4, 6, 12, 18, 24, 30, 42, 60, 72, 102, 108, 138, 150, 168, 180, 192, 198, 228, 240*

*2 seqfan posts*

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

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