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 A181414 Products of exactly two Pillai primes. 0

%I

%S 529,667,841,1357,1403,1541,1633,1711,1769,1817,1909,1943,2059,2291,

%T 2407,2507,3161,3481,3599,3721,3953,4087,4189,4331,4489,4661,4757,

%U 4819,4897,5041,5063,5293,5561,5609,5893,6241,6431,6557,6649,6889

%N Products of exactly two Pillai primes.

%C It would not be right to call these "Pillai semiprimes" as that would better describe semiprimes k such that there exists an integer m such that m!+1 is 0 mod k and k is not 1 mod m.

%C There are no pairs (n, n+1) in this sequence since all terms are odd. The first few n such that n and n+2 are in the sequence are 11771, 14099, 19337, 32729, 32741, 34829, 37391, 38249, 39467, 40319, 41747, ... - _Charles R Greathouse IV_, Jan 28 2011

%F {A063980(i) * A063980(j)}.

%e a(2) = 23*29.

%Y Cf. A001358, A063980.

%K nonn,easy

%O 1,1

%A _Jonathan Vos Post_, Jan 28 2011

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Last modified July 20 14:12 EDT 2019. Contains 325182 sequences. (Running on oeis4.)