Numbers n such that tau(tau(n))= rad(n).
1, 2, 4, 16, 27, 64, 72, 96, 108, 288, 432, 486, 648, 768, 972, 1024, 1536, 1728, 3456
2 seqfan posts
Sun Jun 13 08:51:05 CEST 2010 [seqfan] Re: (3^n+1)/2 is prime, A171381
Sun Jun 13 07:24:58 CEST 2010 [seqfan] (3^n+1)/2 is prime, A171381
Index of A-numbers in seqfan: by ascending order
by month
by frequency
by keyword
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