OFFSET
1,1
COMMENTS
Squarefree integers m congruent to 1 modulo 4 such that the minimal solution of the Pell equation x^2 - d*y^2 = +-4 has both x and y even.
The sequence contains the squarefree numbers congruent to 5 modulo 8 that are not in A107997.
This sequence contains all numbers of the form 4*k^2+1 (k > 1) that are squarefree.
REFERENCES
Z. I. Borevich and I. R. Shafarevich. Number Theory. Academic Press. 1966.
LINKS
EXAMPLE
33 is in the sequence since the fundamental unit of the field Q(sqrt(33)) is 23+4*sqrt(33).
53 is not in the sequence since the fundamental unit of the field Q(sqrt(53)) is 3+omega, where omega = (1+sqrt(53))/2.
CROSSREFS
KEYWORD
nonn
AUTHOR
Emmanuel Vantieghem, Mar 07 2017
STATUS
approved