Project Euler #221: Alexandrian Integers

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    1000 queries of nth value in the known integer sequence : https://oeis.org/A147811
    Sample intput/output : https://oeis.org/A147811/b147811.txt
    The numbers are of the form p(p+d)(p+(p^2+1)/d), where d runs over divisors of p^2+1 and p runs over all positive integers.
    As the numbers are of the form p^4, int64 is not sufficient.
    The real challenge seems to resides inside divisors of p^2+1.
    Prime factors of p^2+1 are always 4k+1 or 2.

  • + 0 comments

    Hi.. I'm trying to understand this problem but I can't realize how to get p, q and r values. Should I have to generate them? I understand that, but If I throw 3 loops to increase them, then when to stop the last one to move hte first forward and iterate again?..I think is missing explanation.

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    Is this doable without calculating every Alexandrian Integers from the beginning ? Is there a better equation than pq + pr + qr = 1?

  • + 1 comment

    Why does it shows terminated due to timeout ? My first test case is passed but rest all are not getting evaluated.

  • + 0 comments

    Please notice that the input stype

    other test case may not in the ascending order, it could be 3,12,16,25
    means: 3 outputs in total, 12th alex number, 16th alex number, 25th alex number,

    OMG, got this wrong all the time, the test case is really confusing