A place to air possible concerns or difficulties in understanding ProjectEuler problems. This forum is not meant to publish solutions. This forum is NOT meant to discuss solution methods or giving hints how a problem can be solved.

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I don't understand what is meant by integer coordinates on the surface. If the radius is r, does that mean that there are points 0 to r going from equator to pole?

EDIT: Okay, I think I get it. The center is 0, 0, 0. A Point(x, y, z) is on the surface, if x, y and z <= r and that coordinate is actually distance r away from Point(0, 0, 0). Is that correct?

I can't seem to get the right answer for this problem even though I get the right value of A(14). I've looked over my algorithm several times, and I'm wondering if there's some precision issue going on (although, it seems unlikely since there aren't that many operations, so I'm really puzzled). Can someone please check if these 3 arbitrarily selected values of A(r) look correct? (I hope this is OK; you need 50 of them to compute the final answer, and these aren't like the most "difficult" cases or anything AFAICT).
A(5) = 2.724572812036574
A(27) = 0.07520891357997117
A(30) = 0.5607476454096538
EDIT: Ahhh never mind, I found a stupid bug in the computation.

I can't seem to get the right answer for this problem even though I get the right value of A(14).

As with the last comment, i am also in the same situation - having looked through my code for bugs and missing coordinates and cannot find any error.
I have also checked my even r against the r/2 and there is no issue - i am completely lost as to what could be wrong.
Could somebody who has solved it allow me to PM a list of my values for A(1...50)??