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Tatsuru Watanabe's set of 47 squarefree numbers whose reciprocals add to 1, with the property that each number has exactly two distinct prime factors.
1

%I #53 Oct 10 2020 12:15:38

%S 6,10,14,15,21,22,26,33,34,35,38,39,46,51,55,57,58,62,65,69,74,82,85,

%T 86,87,91,93,95,106,111,123,133,145,155,159,185,203,215,253,265,287,

%U 319,493,583,731,851,1073

%N Tatsuru Watanabe's set of 47 squarefree numbers whose reciprocals add to 1, with the property that each number has exactly two distinct prime factors.

%C This is one of the 17 sets given in the link below.

%H Carlos Rivera, <a href="http://www.primepuzzles.net/problems/prob_035.htm">Problem 35. More wrong turns...</a>, The Prime Puzzles and Problems Connection.

%H Tatsuru Watanabe, <a href="https://arxiv.org/abs/2009.03275">New examples of the representation of 1 by the sum of reciprocals of semiprime numbers</a>, arXiv:2009.03275 [math.NT], 2020.

%H <a href="/index/Ed#Egypt">Index entries for sequences related to Egyptian fractions</a>

%Y Cf. A201650.

%K nonn,fini,full

%O 1,1

%A _Michel Marcus_, Sep 08 2020