Year numbers, i.e. phi(n) = 2 phi(sigma(n)), divisible by a 5th prime power.
1811079, 4473387, 67009923, 77242167, 88605819, 110475819, 120781449
2 seqfan posts
Wed Aug 18 04:58:00 CEST 2010 [seqfan] Re: not all prime
Wed Aug 18 03:34:41 CEST 2010 [seqfan] Re: not all prime
Index of A-numbers in seqfan: by ascending order
by month
by frequency
by keyword
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