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%I #29 Mar 17 2020 21:17:17
%S 1729,13981,88537,51319,137149,548497,285541,3372529,18326641,1152271,
%T 1809641,3828001,4814857,4797703,79230049,4413223,4209661,19703611,
%U 3882139,50357677,70611161,26536591,175493677,85409941,12932989,84350561,192754871,59756863
%N Numbers that occur more than once in A193873, in order of appearance.
%C Note that a(1) = 1729 is known as the Hardy-Ramanujan number (see A001235).
%C Apparently these numbers occur only twice in A193873.
%C Many of these numbers occur more than twice. For example, 812405017 occurs 3 times, a(67), a(134), and a(268). _Robert Price_, Mar 17 2020
%H Robert Price, <a href="/A194263/b194263.txt">Table of n, a(n) for n = 1..2554</a>
%F It appears that a(n) = A193873(2*n+1).
%F This conjecture only holds for n<62: a(62)=A193873(124)=A193873(2n)=620378449
%F , a(63)=A193873(125)=A193873(2n-1)=424315751
%F . _Robert Price_, Mar 17 2020
%e 1729 is in the sequence because the Hardy-Ramanujan number is also the smallest product of three distinct primes of the form 3*k+1 and also of the form 6*k+1, so 1729 occurs more than once in A193873.
%Y Cf. A001235, A154729, A193869, A193873.
%K nonn
%O 1,1
%A _Omar E. Pol_, Sep 02 2011
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