**a(1) = 1, a(2) = 2, a(n) = smallest number not occurring earlier such that the sum of three successive terms is prime.**

*1, 2, 4, 5, 8, 6, 3, 10, 16, 11, 14, 12, 15, 20, 18, 9, 26, 24, 17, 30, 32, 21, 36, 22, 13*

*1 seqfan posts*

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

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