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A336791 Incrementally largest values of minimal x satisfying the equation x^2 - D*y^2 = -2, where D is an odd prime number. 2
1, 3, 13, 59, 221, 8807, 527593, 52778687, 113759383, 13458244873, 313074529583, 1434867510253, 30909266676193, 842239594152347, 1075672117707143, 29204057639975683, 52376951398984393, 4785745078256208692917, 15280437983663153103594943 (list; graph; refs; listen; history; text; internal format)



Analogous to A033315 for x^2-D*y^2=1, and D required to be prime.


Table of n, a(n) for n=1..19.

Christine Patterson, Cocalc (Sage) program


For D=43, the least x for which x^2-D*y^2=-2 has a solution is 59. The next prime, D, for which x^2-D*y^2=-2 has a solution is 59, but the smallest x in this case is 23, which is less than 59. The next prime, D, after 59 for which x^2-D*y^2=-2 has a solution is 67 and the least x for which it has a solution is 221, which is larger than 59, so it is a new record value. 67 is a term of A336790 and 221 is a term of this sequence, but 59 is not a term of A336790 because the least x for which x^2-47*y^2=-2 has a solution at D=59 is not a record value.


Cf. A033315, A336790.

Sequence in context: A151227 A151228 A339881 * A268596 A199297 A152594

Adjacent sequences:  A336788 A336789 A336790 * A336792 A336793 A336794




Christine Patterson, Oct 14 2020



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Last modified May 16 15:55 EDT 2021. Contains 343949 sequences. (Running on oeis4.)