[seqfan] Re: Not expressible as x^3+-y^2

[Jack Brennen]

Hugo:

At first I thought that your sequence consisted of those numbers
which are in both A54504 & A81121, but those sequences allow for
x==0 or y==0.

Side note... it is amusing that A54504 is marked as an 'easy'
sequence, but A81119 is markes as a 'hard' sequence -- note that
A54504 is exactly the sequence of indices of the zeroes in A81119.
It might be accurate that one is easy and the other is hard, but
I am not sure that I agree that A54504 should be 'easy' ...