[seqfan] Partial sums of even and odd semiprimes

israel at math.ubc.ca israel at math.ubc.ca
Mon Apr 10 04:34:52 CEST 2023


Zak Seidov pointed out to me that 62234 and 199370 are partial sums of both
the even semiprimes and the odd semiprimes:
62234 = 4 + 6 + 10 + 14 + ... + 1226 (112 terms)
      = 9 + 15 + 21 + 25 + ... + 779 (158 terms)
199370 = 4 + 6 + 10 + 14 + ... + 2302 (190 terms)
       = 9 + 15 + 21 + 25 + ... + 1385 (284 terms) I did not find any more 
examples using semiprimes up to 10^7. Are there likely to be any others? 
Can anyone find some? If not, two terms would normally be too few for a 
sequence, but maybe an exception could be made in this case?

Cheers,
Robert


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