**a(1) = 1; if n = k-th prime, a(n) = k; otherwise write all prime factors of n in nondecreasing order, replace each prime by its rank, and concatenate the ranks.**

*1, 1, 2, 11, 3, 12, 4, 111, 22, 13, 5, 112, 6, 14, 23, 1111, 7, 122, 8, 113, 24, 15, 9*

*3 seqfan posts*

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

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